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Using Arduino => Project Guidance => Topic started by: LEGO-lars on Jul 09, 2012, 08:29 pm

Title: Measuring the weight of a beehive
Post by: LEGO-lars on Jul 09, 2012, 08:29 pm
Hi
This is my first ever post on the arduino forum, so be gentle ;)

I would like to use an arduino to measuring the weight of some beehives, and then have a gsm mudule send the result as an sms to my cellphone. Something like this:http://www.bienenwaage.de/englisch/beehivescales.html (http://www.bienenwaage.de/englisch/beehivescales.html)

The spec i need from the scale is:
1. Be able to measure weights from 0 - 150 kg
2. Have a tolerance on +- 1-2 kg
3. Sensor can be calibrated in the beginning of the season, and then stand for about five months without calibration or zeroing.
4. The sensor is placed outside so it have to deal with varius humidity levels and temperaturs from 0 - 35 degrees Celsius.
5. If the prototype works promising, I would like to build 20-30 scales, so the parts needs to be as cheap as possible.

My question is what kind of sensor can i use to achieve this specs? Is loadcells the only way to go? I thought loadcells had a problem with drifting during long time sessions(and they are a bit expensive ;))

Thank you for your reponses.
Title: Re: Measuring the weight of a beehive
Post by: jackrae on Jul 09, 2012, 08:44 pm
Whatever method you use you could also produce a dummy beehive (to act as a reference weight) using the same type of sensor.  Then as the reference weight changes with the temperature, humidity, rain, wind, etc your dummy beehive's measured weight can be used to compensate your actual weight measurements.

Title: Re: Measuring the weight of a beehive
Post by: PeterH on Jul 09, 2012, 09:04 pm
I suppose you could make a DIY weight sensor using springs and position sensors (potentiometer etc) but for beehives I guess you want the whole thing to be solidly mounted and not move around, which might rule out that kind of approach. If you fancy making and calibrating your own load cell, you can buy a strain gauge for just a few quid. Then you have to figure out how to mount it, read it, calibrate it, compensate for temperature drift and so on. It only needs time and effort rather than money, but I don't know how that sort of thing appeals to you.
Title: Re: Measuring the weight of a beehive
Post by: radman on Jul 09, 2012, 09:34 pm
150kg is pretty heavy and +/- 1-2kg seems quite crude, are those figures correct?
I though you would be wanting to watch the honey come in a jar at a time  :)

Maybe I am going off at tangents. Bees probably don't mind a bit of movement, so perhaps the hive could be suspended from a spring balance and you just send a picture of several hives from time to time. Maybe you could convert weight to pressure, if that is cheaper/easier to measure.

Sorry just thinking out loud.
Title: Re: Measuring the weight of a beehive
Post by: retrolefty on Jul 09, 2012, 10:25 pm
While load cells can be costly they are the best device for this kind of application. Some time you can find them surplus on E-bay for better prices. The idea of having a reference weight on one addition channel is a good one and would allow software compensation to all the other channels. Load cells are low level (millivolt) sensors and you will usually require external op-amps for proper amplification.


Lefty
Title: Re: Measuring the weight of a beehive
Post by: LEGO-lars on Jul 09, 2012, 11:57 pm
Thank you for all the good ideas. keep them coming XD. I like the idea of a dummy beehive and the diy spring scale. One problem whith the spring idea is that the scale has to be placed directly under the beehive so it is not in the way when I work. to prevent the hive from lean over and tip in the wind I would need some short and hard springs. Then i would have to mesure very tiny contraction of the springs, maybe in tens of a millimeter. I am not sure how to do that.

@radman
A full hive can weigh up to around 100 kg. the extra 50 kg is just to be at the safe side.
The goal of the weighing is to check if the bees have enough food, having to little space, to see were the bees collect most honey(so i can move more bees over there), and to detect swarming(when the bees leave the hive).

@retrolefty
It looks that mabye load cells is the way to go. A beefy shear beam load cell, right under the hive should do the trick. On eBay there is a lot of el cheapo 20 dollar load cells, but none of them goes as high as 150 kg. In that weight class, i can only find industrial 300 dollar load cells :(
Title: Re: Measuring the weight of a beehive
Post by: radman on Jul 10, 2012, 11:32 am
You can get carbon impregnated foam material whose resistance changes when compressed. You could put the hives on that, but accuracy, range and rain may be an issues. I suppose the foam could be placed inside an impermiable coating.
Title: Re: Measuring the weight of a beehive
Post by: LEGO-lars on Jul 11, 2012, 10:57 pm
Hi.
A little update.
After a bit research, a load cell seems like the best solution. I just have to find one cheap enough ;)

My plan so far is to in each beefarm have one control box(master), and several scales(slave) that will communicate with each other using wireless transcivers.

The control box will be powered by a lead acid battery, and contain an microcontroller, a GSM module, a RTC, a wireless transceiver, sensors for measurment of temperature, humidity and rainfall and maybe a load cell with a fixed load for using as a referance.

For the hive scales I was tinking of using a single load cell made for platform scales. For the op-amp I was thinking about the ina125 http://www.ti.com/lit/ds/symlink/ina125.pdf (http://www.ti.com/lit/ds/symlink/ina125.pdf) since it got an onboard voltage referance and a sleep mode.
For communication I have looked at various NRF24L01+ transceiver module since it is cheap and have a low power consumption.

To power the scale I was thinking of using a small solar panel to charge up a supercapasitor. when the supercapasitor is charged up, the atmega will wake up from sleep, measure the weight of the hive, transmit it to the master, and then go back to sleep. I only need 5 or 6 samples during the day, so the atmega and radio, will be in sleep mode for 99% of the time.

Does this sounds manageable solution? I do not have much experience with op-amps, and I have never used wireless transceivers. So if someone has any opinions regarding to these, I would be very grateful
Title: Re: Measuring the weight of a beehive
Post by: retrolefty on Jul 12, 2012, 12:43 am

Hi.
A little update.
After a bit research, a load cell seems like the best solution. I just have to find one cheap enough ;)

My plan so far is to in each beefarm have one control box(master), and several scales(slave) that will communicate with each other using wireless transcivers.

The control box will be powered by a lead acid battery, and contain an microcontroller, a GSM module, a RTC, a wireless transceiver, sensors for measurment of temperature, humidity and rainfall and maybe a load cell with a fixed load for using as a referance.

For the hive scales I was tinking of using a single load cell made for platform scales. For the op-amp I was thinking about the ina125 http://www.ti.com/lit/ds/symlink/ina125.pdf (http://www.ti.com/lit/ds/symlink/ina125.pdf) since it got an onboard voltage referance and a sleep mode.
For communication I have looked at various NRF24L01+ transceiver module since it is cheap and have a low power consumption.

To power the scale I was thinking of using a small solar panel to charge up a supercapasitor. when the supercapasitor is charged up, the atmega will wake up from sleep, measure the weight of the hive, transmit it to the master, and then go back to sleep. I only need 5 or 6 samples during the day, so the atmega and radio, will be in sleep mode for 99% of the time.

Does this sounds manageable solution? I do not have much experience with op-amps, and I have never used wireless transceivers. So if someone has any opinions regarding to these, I would be very grateful



Well it sounds like you have a good grip on what is required to perform what you have defined needing to be done. As far as manageable, that would depend on your experience and ability to keep plugging away at it. I would suggest you approach the project in steps. I would recommend you first work on getting the wireless network working between the master and the number of slaves you will be using. Wireless (software & hardware) can be very taxing to get going from basic components, it's never as easy as it first sounds. Once that is mastered and working well then you can make the higher cost investment in the load cells and support components and the mechanical packaging, etc.

Good luck
Lefty
Title: Re: Measuring the weight of a beehive
Post by: ex-Gooserider on Jul 12, 2012, 07:24 am
Just as a thought, have you tried looking at cheap digital bathroom scales as a source of load cells?  The ones I've seen typically can deal with weights up to around 300lbs, which sounds like the range you are after...

It does sound like an interesting project, I might be interested in it myself, as I'm also a small scale beekeeper (2 hives)

ex-Gooserider
Title: Re: Measuring the weight of a beehive
Post by: LEGO-lars on Jul 13, 2012, 11:22 pm
Thank you for all the help. Now I feel this project is a bit more doable. I have ordered some cheap NRF24L01+ modules from eBay, as well as some small solar cells and supercaps. Now I will learn to use the transceivers, and testing their range and differend master/slave setups.
Looks like i have som work to do with the atmega328P also. I would like it to run in the same voltage range as the NRF24L01+ (1.9 - 3.6V) which means I have to use a slower clock. I would also like to remove the arduino bootloader so I avoid the bootloader delay waste a lot of power during powerup.

@ex-Gooserider
I have been thinkin about using bathroom scales as well. But I am under the impression that the load cells in these scales are of a very bad quality. And for some reason it feels a bit wrong to buy 30 bathroom scales, remove one component and then throw avay the rest. :P
But if i can't find anything else, it's worth a try. :)

LEGO-lars
Title: Re: Measuring the weight of a beehive
Post by: xavier785 on Oct 21, 2012, 07:26 pm
Hi ,

I am busy on a similar project. with :
-2 strain gauges from a bathroom scale ( there are 4 in each lowcost bathroom scale) mounted in weadstone bridge on a ad620 precision  amp ( cheaper than the texas ina125 )
-4 ds1820 temp sensor
-HD44780 LCD
-DS1302 RTC
-sd slot for data storage ( tested appart and working but not implemented yet in this specific project )

the objective is to read temp + weight each 24 hours and  to store or send it
accuracy is 100gr , but one of my biggest problem was until now to keep the weight readings stable

Maybe we could share our respective experience ?
Title: Re: Measuring the weight of a beehive
Post by: LEGO-lars on Oct 22, 2012, 10:02 pm
Hi xavier :)

Nice to hear about other peaple having the same project. Do you only store the data from your scale, or do you have some method for reading the weight remotely?

An update on my work:
I made a prototype using this load cell:http://www.aliexpress.com/item/100kg-200kg-300kg-weighing-scales-load-cell-for-platform-scales/624403255.html (http://www.aliexpress.com/item/100kg-200kg-300kg-weighing-scales-load-cell-for-platform-scales/624403255.html)  and the ina122 amplifier. This setup gives me a great accuracy and almost no temperature drift. However, the ina122 is getting a bit unstable when I am powering it with a 3v battery, so I am going to try some other amplifiers like the ina333 or AD8553.

LEGO-lars
Title: Re: Measuring the weight of a beehive
Post by: gardner on Oct 22, 2012, 11:25 pm
Most of the applications I have seen with load-cells call for periodically re-taring or zeroing out the reading.  Just comparing the reading with a similar load cell at a known load doesn't really tell you that much.  You have to un-load THIS load cell and take a reference reading, then load it again, to get a good useful reading from a given load cell.

So in my project, which is for measuring the weight of a 300lb LPG tank, or for the present project, to weigh a beehive, a critical requirement is that the propane tank or beehive is going to want to sit on the load cell for weeks or months at a stretch, and you still want decent readings -- say within 1 part in 100.  No one's going to come around and lift off the hive every few hours to zero out the load cell -- it has to remain accurate under constant load, day in, day out.

For this type of application, I have imagined two approaches:

(1) build a balance-lever linkage system that enables a load cell to be presented with 1:1000 of the load.  Have the small load spend most of it's time against a stop.  Once in a while, when a reading is needed, use a servo or similar mechanical linkage to push the load cell against the load to move it away from the stop.  Take your reading, retract the load cell.  This way the cell spends most of its time un-loaded, so fatigue and creep don't affect it, and it is always neatly tared to zero before each reading.

(2) build a pneumatic balloon system under the load, like a hot water bottle.  Inflate it and seal it up, then just measure the pressure in the balloon.  If its hard to keep the balloon inflated all the time, then let the weight rest at the bottom and make a contact closure.  When  reading is needed, pump air into the balloon until the contact closure opens, take pressure readings for a while, then kill the pump and let the weight settle back against its stop.

I'm not super enamored of either, really, but they're the best solution I can up with for the re-tare problem.
Title: Re: Measuring the weight of a beehive
Post by: LEGO-lars on Oct 24, 2012, 08:40 pm

Most of the applications I have seen with load-cells call for periodically re-taring or zeroing out the reading.  Just comparing the reading with a similar load cell at a known load doesn't really tell you that much.  You have to un-load THIS load cell and take a reference reading, then load it again, to get a good useful reading from a given load cell.

So in my project, which is for measuring the weight of a 300lb LPG tank, or for the present project, to weigh a beehive, a critical requirement is that the propane tank or beehive is going to want to sit on the load cell for weeks or months at a stretch, and you still want decent readings -- say within 1 part in 100.  No one's going to come around and lift off the hive every few hours to zero out the load cell -- it has to remain accurate under constant load, day in, day out.

For this type of application, I have imagined two approaches:

(1) build a balance-lever linkage system that enables a load cell to be presented with 1:1000 of the load.  Have the small load spend most of it's time against a stop.  Once in a while, when a reading is needed, use a servo or similar mechanical linkage to push the load cell against the load to move it away from the stop.  Take your reading, retract the load cell.  This way the cell spends most of its time un-loaded, so fatigue and creep don't affect it, and it is always neatly tared to zero before each reading.

(2) build a pneumatic balloon system under the load, like a hot water bottle.  Inflate it and seal it up, then just measure the pressure in the balloon.  If its hard to keep the balloon inflated all the time, then let the weight rest at the bottom and make a contact closure.  When  reading is needed, pump air into the balloon until the contact closure opens, take pressure readings for a while, then kill the pump and let the weight settle back against its stop.

I'm not super enamored of either, really, but they're the best solution I can up with for the re-tare problem.


The need for zeroing of the load cell was a consern for me too. However my 200kg load cell have been standing on my kitchen bench with a constant load for over a week, and it is only drifting like +/- 20g (a little worse when the temperature changes, but not to bad).
If I had zeroed my scale before each measurement (and had higher resolution on my ADC), I would mabye get ten times better accuracy. But it all comes down to if you really need that extra accuracy. In my case I did not. :)

LEGO-lars
Title: Re: Measuring the weight of a beehive
Post by: gardner on Oct 24, 2012, 10:53 pm

my 200kg load cell have been standing on my kitchen bench with a constant load for over a week, and it is only drifting like +/- 20g (a little worse when the temperature changes, but not to bad).


Interesting, that's a good start.  It sounds more stable than I would have guessed.  What % of load capacity is on there?

How about outside in the weather?  For a year?

If you could demonstrate ~ +/- 1% of full scale accuracy, while sitting with 50% of rated load for 10 months across temperature changes of +30C to -20C, then I'll be convinced.
Title: Re: Measuring the weight of a beehive
Post by: LEGO-lars on Oct 26, 2012, 01:31 pm
Hi
In my load-cell test I used a 20kg load. I am not sure if using a higher load will make a difference since it is the offset of the load-cell and not the gain which is causing the error.

For my next tests of the load-cell, I will probobly leave it outside for a month or two, logging the load and temperature. Maybe I can give you some better answers then :)
Title: Re: Measuring the weight of a beehive
Post by: gardner on Oct 26, 2012, 03:51 pm
Load cell is actually a strain gauge attached to a beam, in such a way as to measure the elastic deformation of the beam under load.  A higher load will accelerate the effects of creep (https://en.wikipedia.org/wiki/Creep_%28deformation%29), which will be one of the modes of long term reading drift.  Affects like work-hardening, corrosion and fatigue will also be there.

My working assumption is that those effects are going to make long term readings from a constantly loaded load-cell drift in such a way that you can't really trust the reading you get, until you, at least, re-tare the load cell to a known load.  If you can prove I'm crazy, that would be great.
Title: Re: Measuring the weight of a beehive
Post by: Ickmund on Feb 06, 2013, 11:53 am
Very interesting project, would love to know how it has progressed!

I'm doing the very same thing, environmental monitoring of beehives, including weight. Just as you have, we've identified the weight to be the biggest issue. From what I've heard, constant weight higher than 10% on a load cell will strain it over time. I'm hoping to get to testing this within the next few weeks, but I don't know if testing will be done in time for this season.

On the electronic side of things I've ordered Moteino:s. They sell for $16, including radio at 434MHz, and should be Arduino-compatible. It will probably be a couple of weeks before they arrive, but I'll come back with some details once I've gotten to play with them a bit.

http://lowpowerlab.com/blog/2012/12/20/moteino-the-wireless-low-power-low-cost-arduino-clone/

I should mention that this will be my first "Arduino" project, very excited!  :D
Title: Re: Measuring the weight of a beehive
Post by: Clemens on Feb 12, 2013, 04:18 pm
Hi Lars, what is going on in your project? I'm interested in hive scales also and did some research. Nice to see that cheap load cells seams to work. Do you have some new recommendations for the amplifier? 
Title: Re: Measuring the weight of a beehive
Post by: LEGO-lars on Mar 07, 2013, 11:37 pm
Time for an update on my project :)
lately I have been focusing on the wireless interface and power consumption of the sensor nodes. The ina333 op-amp workes great in my low voltage setup.
I have a prototype up and running on a breadboard(see the schematic)
(http://bildr.no/thumb/1409684.jpeg) (http://bildr.no/view/1409684)

To optimize the battery life, I am running a barebone AtMega328P on the internal 1Mhz clock, the bod level is set to 1.8v and is software-disabled while the processor is sleeping.
Also i am using a pnp-transistor to shut off the current to the loadcell and op-amp, so they only consume current a few milliseconds while sampling.
I am also using the Collector voltage of the transistor as my analog reference, so the voltagedrop of the transistor won't affect my measurements.
Since The Internal ocilator is'nt accurate enough, I connected a 32.768 khz crystal to the chip's clock-pins. This crystal feeds Timer2 and creates an accurate interupt every second. This way the the AtMega also works as an RTC, and I save the cost and powerconsuption of an external RTC.
All in all including the radio tranciver my crappy multimeter shows a current consumption of 2-5µA :smiley-eek: when everything except the 32khz crystal and timer2 is sleeping.

The wireless comunication was a real twist. I want the sensor nodes to sleep as much as possible, and there will be a lot of sensornodes trying to communicate with one "master-module".
The solution I foud, is to let the master-module decide when the sensor-node can start transmitting. So when a sensor-node is waking up from sleep, the master-module will already had started listening to that exactly node. Then when the sensor-node has sent it's data to the master-module, the master will respond by sending how long time to next datatransfer. The whole prosses of waking up the prosessor, wait for the op-amp to stabilize, take ten samples and calculate the average, sending the data, reciving the time to next datatransfer, and go back to sleep only takes about 100ms with an average current consumption of 6mA :smiley-eek:
If i take one measurment each hour, I would get an average current consumption of 5.25 µA 8)
Anyone who know how long this thing will run on a cuple of AA? ;)

the next tasks on my todo list:
1. Use the internal bandgap reference of the AtMega chip to measure the battery voltage, and make a low battery warning.
2. upload the measurements to Cosm.com using a gprs-module. (I just smoked my gprs-shield so this can take some time :))
3. put everything in a watertight box and do a real longtime outdoor test of the loadcell.


ps. It looks like this thread is turning into a worklog. Mabye a moderator can move this thread into a more suitable category.

Title: Re: Measuring the weight of a beehive
Post by: GoForSmoke on Mar 07, 2013, 11:59 pm
I'm not sure that this will be good for beehives but if you have a mass that can move freely and an accurate accelerometer, especially at low G's, then if you apply a known force... F=MA.



Title: Re: Measuring the weight of a beehive
Post by: Henry_Best on Mar 08, 2013, 05:20 am


For this type of application, I have imagined two approaches:
...
(2) build a pneumatic balloon system under the load, like a hot water bottle.  Inflate it and seal it up, then just measure the pressure in the balloon.  If its hard to keep the balloon inflated all the time, then let the weight rest at the bottom and make a contact closure.  When  reading is needed, pump air into the balloon until the contact closure opens, take pressure readings for a while, then kill the pump and let the weight settle back against its stop.


That has given me an even simpler idea of how you could solve the problem. Fill the 'balloon' with (coloured?) oil and use a manometer type system (a U tube) to measure the pressure (= weight). Detecting how far up a tube the fluid level is would be far simpler than using stress gauges, which will have to be regularly zeroed. The narrower the tube, the more accurate it will be. You could use ultrasound to measure the distance of the fluid from the top of the tube. You may need a floating passive reflector for this. That way, no pump is needed and readings can be taken at any time. You will still need a 'dummy' hive to take into account ambient temperature (and, therefore, volume) variations. You'll also need to calibrate the tube (once) by adding known weights onto the 'balloon'.
Title: Re: Measuring the weight of a beehive
Post by: Chagrin on Mar 08, 2013, 07:52 am
I'm not sure a "balloon" type system would work quite as expected. When weight is added to the hive the balloon will flatten out and result in a non-linear pressure reading at your manometer?

Using the example of a car tire, pressure measured in PSI, the footprint (in square inches) of the tire multiplied by the inflation pressure equals the weight supported by the tire (an "ideal" tire, ignoring sidewall stiffness, etc.). When weight is added the footprint can increase and the pressure can stay near or at the original pressure.

I might be totally off my rocker.

Title: Re: Measuring the weight of a beehive
Post by: GoForSmoke on Mar 08, 2013, 11:52 am
I'd suggest using magnets and coils to raise the hive instead of a balloon but the fields might have a long term effect on the bees.



Title: Re: Measuring the weight of a beehive
Post by: LEGO-lars on Mar 08, 2013, 02:57 pm
Thank you for your ideas but I have decided to use loadcells for my project. It looks like my prototype using a loadcell meets my requirements in both accuracy, power consumption, cost and simpleness. :)
Title: Re: Measuring the weight of a beehive
Post by: GoForSmoke on Mar 08, 2013, 03:35 pm
That's great! The world does need more bees.
Title: Re: Measuring the weight of a beehive
Post by: Henry_Best on Mar 09, 2013, 03:58 am

I'm not sure a "balloon" type system would work quite as expected. When weight is added to the hive the balloon will flatten out and result in a non-linear pressure reading at your manometer?

Using the example of a car tire, pressure measured in PSI, the footprint (in square inches) of the tire multiplied by the inflation pressure equals the weight supported by the tire (an "ideal" tire, ignoring sidewall stiffness, etc.). When weight is added the footprint can increase and the pressure can stay near or at the original pressure.

I might be totally off my rocker.


Not off your rocker, but have you thought about a flat square 'balloon', the same size as the base of the hive? Remembering that he's starting with 100+ Kgs on it, the few grams more or less wouldn't make any difference at all to the footprint.

But after sleeping on the idea, I realised that a manometer system would need an equal weight of oil to balance the hive. 200 litres of hydraulic oil doesn't come cheap!
Title: Re: Measuring the weight of a beehive
Post by: GoForSmoke on Mar 09, 2013, 06:50 am


I'm not sure a "balloon" type system would work quite as expected. When weight is added to the hive the balloon will flatten out and result in a non-linear pressure reading at your manometer?

Using the example of a car tire, pressure measured in PSI, the footprint (in square inches) of the tire multiplied by the inflation pressure equals the weight supported by the tire (an "ideal" tire, ignoring sidewall stiffness, etc.). When weight is added the footprint can increase and the pressure can stay near or at the original pressure.

I might be totally off my rocker.


Not off your rocker, but have you thought about a flat square 'balloon', the same size as the base of the hive? Remembering that he's starting with 100+ Kgs on it, the few grams more or less wouldn't make any difference at all to the footprint.

But after sleeping on the idea, I realised that a manometer system would need an equal weight of oil to balance the hive. 200 litres of hydraulic oil doesn't come cheap!


Or you could measure the height of the flattened balloon... I would use an inner tube to rest something on and maybe fill with dry CO2 or nitrogen.

But I think that his load cells are better than springs of any type.

I understand that putting mechanical strain on any conductor changes its resistance, even copper.




Title: Re: Measuring the weight of a beehive
Post by: Clemens on Mar 15, 2013, 11:45 pm

2. upload the measurements to Cosm.com using a gprs-module. (I just smoked my gprs-shield so this can take some time :))


Thanks for this update! May be this combined board is usable: http://imall.iteadstudio.com/im120411004.html It is an Arduino, GSM, XBee, SD-Card on one board. It is cheap, but I do not know how power saving can be done.

Perhaps the new Arduino GSM shield is more power saving and battery compatible but there are some inconsistent information atm:
http://arduino.cc/forum/index.php/topic,148708.msg1156939.html#msg1156939

When <400 mA peak current is correct this would be an interesting board. But you have to pay nearly 100 Eur for the board only!
Title: Re: Measuring the weight of a beehive
Post by: Clemens on Mar 20, 2013, 12:42 am
Lars, what resolution do you have with your scale? We had some ideas and came to the solution not to use an amp but instead an external ADC with a higher resolution than the 10bit Arduino, do you use an other board (e.g. the DUE has a 12 bits resolution)?, see http://hackerbee.com/2013/03/18/100-hive-losses-this-year/ or did we forget something? and a resolution of max load / 1024 is with the INA333 possible? I think it amplifies only the signal or does it do any digitalization?
Title: Re: Measuring the weight of a beehive
Post by: LEGO-lars on Mar 26, 2013, 09:03 pm
Hi Clemens :) Thanks for the link. A lot useful information on that page.
You are right in that the arduino 10 bits of resolution is a bit low.
However, there is a way to increse the resolution of the ADC called oversampling. http://www.atmel.com/images/doc8003.pdf
In short, 16 10-bits sampeles are equal to one 12-bit sample.
In my scale, I have no problem to get a stable resolution of 0.1kg.
Title: Re: Measuring the weight of a beehive
Post by: motiTheWonderDog on Jun 23, 2013, 10:09 am

http://dl.dropboxusercontent.com/u/128833299/bees.htm

Uses 50kg Load Sensor PPSEN-10245 for weight monitoring.

Photo Interrupter GP1A57HRJ00F to count the bees going in and out of the hive.

Title: Re: Measuring the weight of a beehive
Post by: toadstul on Nov 06, 2013, 04:24 pm
What has happen to this project?
Is there any farther progress?
Title: Re: Measuring the weight of a beehive
Post by: LEGO-lars on Nov 06, 2013, 09:03 pm
Hi toadstul.
I have been quite busy with some other projects lately (and got a bit bored :smiley-red:), so nothing has been done on this project in the last 6 months.
However, before I took a break I was doing great progress.
I've got the PCB for the wireless scales manufactured. I've got the the power consumption low enough for the scale to work several seasons before battery change is necessary. I have made the base station with the GPRS-module, a wether station, and a solar panel.
I've also got the whole setup working on my workbench, and uploaded data to Cosm.com.

What remains is to make the actual scale that fits under the beehive.
I also have some problems with the wireless trancievers (probably due to a designflaw on the PCB :smiley-red:).
Then I have to make everything watertight.
On the computer side, I would like to download the data into a spread-sheet, and use some algorithms to calculate which beehive needs attention.

I plan to start up again this winter when I will have some more spare time.

I could probobly post some pictures and explanation of the current setup if there is any interest.

LEGO-lars
Title: Re: Measuring the weight of a beehive
Post by: SirNickity on Nov 06, 2013, 10:35 pm
Measuring bee-hives?   :smiley-eek-blue:

NOPE.  Nope nope nope.  nope.... nope...

*shudder*  nope!
Title: Re: Measuring the weight of a beehive
Post by: zagryl on Nov 07, 2013, 05:07 am
Is there any particular reason you bother yourself with power consumption as you can put a car battery with a solar panel charger to rid yourself of power consumption problems.? It's not like you'll leave your bees to themselves for two seasons?  :)

Or am I missing something?
Title: Re: Measuring the weight of a beehive
Post by: LEGO-lars on Nov 07, 2013, 08:34 pm
The two main reasons for the fiddling with the power consumption, is cost and flexibility. If this system turns out to work, I would like measure all our 200+ hives (my father works full time as a beekeeper). Therefor the cost of each weightscale is critical. Powering the each scale with 2 AAA batteries would be a lot cheaper then using a car battery and solar panel, even if I could power several scales from the same battery.

The second reason is flexibility. When the scale is completely wireless, everything can be hided under the hive with no wires lying everywhere to be tripped over. The hives are also moved a couple of times during the season (to get more honey), so rigging the system up and down have to be easy and fast.

A last benefit with my wireless modular system is that it is easy to add or remove modules from the network. The plan is to let the base station in every bee-farm auto detect the wireless scales without intervention from the user.

Lego-lars
Title: Re: Measuring the weight of a beehive
Post by: odometer on Nov 08, 2013, 02:26 pm
Too bad you can't just use one of these:

http://www.flickr.com/photos/jtr27/8399594421/ (http://www.flickr.com/photos/jtr27/8399594421/)

(Or can you?)
Title: Re: Measuring the weight of a beehive
Post by: toadstul on Nov 13, 2013, 06:57 pm
Hi LEGO-lars
Sorry about the delay of my answer(i was changing  isp)
What method did you follow to lower the power consumption?
What chip did you use to amplify the signal from the loadcell?
You say ''I plan to start up again this winter when I will have some more spare time. I notes that you are from Norway, I think you already have winter up there :P !! So please start again your project asap.
Pictures and explanation...?    of course there is interest !

On my side I have buy already tow arduino uno, tow loadcell 160kg, tow ina125, tow DS3231 rtc, tow DHT22/AM2302 Digital Temperature And Humidity Sensor, and i am waiting an  Arduino GSM Shield (antenna connector).
I plan to connect all these together and get daily reports of weight to my mobile. That will help me to know when the nectar flow stars or ends.
Title: Re: Measuring the weight of a beehive
Post by: Clemens on Nov 13, 2013, 09:54 pm
Power consumption can be done mainly by changing to an barebone Arduino setup, think the most cited article about this is http://gammon.com.au/power .

Quote
The initial outcome is that, to save power, forget about using a development board. Further savings (like reducing clock speed) would be overshadowed by the huge overhead of the voltage regulator and USB interface chip.


I think Lars used as OpAmp an INA333 as linked in an older posting above: http://bildr.no/view/1409684 and no additional ADC so there is really an option for better reading than 0.1 kg resolution.

I see this two options: Use an additional ADC plus OpAmp / PGA  or a chip who has both integrated, see my posting under http://forum.arduino.cc/index.php?topic=198139.0 - so you see, you are not alone. :-) you may also have a look at the Seeeduino Stalker who has a lot of build in (charger circuit, RTC, SD) http://www.seeedstudio.com/wiki/Seeeduino_Stalker_v2.3


Title: Re: Measuring the weight of a beehive
Post by: LEGO-lars on Nov 18, 2013, 09:43 pm
Hi again :)
Here are some pictures of my project so far.
(http://bildr.no/thumb/d0RuSnAr.jpeg) (http://bildr.no/view/d0RuSnAr)
This is the wireless sensor node. The Atmega328 is running at 1 Mhz internal  ocilator. I am using a 32 khz clock-crystal connected to the xtal pins and timer 2, to make a the AVR work as a RTC.
To amplify the loadcell I am using the ina333 op-amp and no additional ADC, but with some oversampling and black magic, I get something that looks like 12 bits of resolution :)  As clements has pointed out, it is possible to use an external ADC, and probably get a better resolution. In my case I could not find anyone that works over the whole voltage span of two AAA batteries.
A P-channel mosfet cuts the power to the loadcell and op-amp when they are not needed.

(http://bildr.no/thumb/VTU4TUF6.jpeg) (http://bildr.no/view/VTU4TUF6)
This is the prototype for the base station. It is using the sim900BE GPRS-module, and have interface for a DHT22 temperature/humidity sensor, and a rain gauge. It also have a solar charge controller.

(http://bildr.no/thumb/dUJJYWRC.jpeg) (http://bildr.no/view/dUJJYWRC)
This is a prototype of the actual scale that fits under the bee-hive. The plan here is to only measure one side of the hive and expect the other side to be equal.  This would make the scale much easier to make, and I could use a smaller and cheaper loadcell. If this method is accurate enough, remains to be seen.

Title: Re: Measuring the weight of a beehive
Post by: GoForSmoke on Nov 19, 2013, 05:08 am
Just wondering how much the bees weigh and if there's times when they're all inside like at night.
Title: Re: Measuring the weight of a beehive
Post by: Clemens on Nov 25, 2013, 11:05 pm
A single bee has a weight of about  0.1 g. So a big hive has 3-4 kg bees. But most changing factor relating to weight is nectar flow and evaporation. Bees bring nectar to the hive with 80 % water. Honey has in the end under 20 % water. The difference must be reduced by the bees.
Title: Re: Measuring the weight of a beehive
Post by: Gert_O on Jan 15, 2014, 09:11 pm
Hi Lego-Lars
Have you got at suitable loadcell for you bi-hive weight ?
I am very interested to here more about your project. Maybe we could help each other. I have acces to very cheap 120 kg full bridge single point loadcells In a month or so.
Is I possible to here more about you have build your hardware, and maybe a little about your software.
I am a be-keeper too, here in DK.
Sorry for my English, it's a little rusty!
Title: Re: Measuring the weight of a beehive
Post by: Clemens on Jan 19, 2014, 01:58 am
Hi Lars, there is a recommendation for an ADS1231 as ADC: 24bit and 128x PGA sounds good to improve accuracy a lot:
http://forum.arduino.cc/index.php?topic=198139.0
Title: Re: Measuring the weight of a beehive
Post by: GoForSmoke on Jan 19, 2014, 07:25 am
I've seen a 12 bit ADC home game controller unit that's already got instructions to use short shielded wires and needs care to not get garbage readings. What care must be taken past 16 bits? They aren't snap-together Lego blocks.
Title: Re: Measuring the weight of a beehive
Post by: Trottel100 on Jan 30, 2014, 06:59 pm
Hi,
how Long stays the battery?
more than one month?

Best regards
Title: Re: Measuring the weight of a beehive
Post by: vasco-vls on Feb 04, 2014, 11:03 am
Hello,

I am working on the same project! I started in July 2013 and at first, I used 4 load cells from cheap digital scale. I connect them together to form Wheatstone bridge, excitation voltage and amplification was done by INA125, analog-digital conversion with internal ADC in ATMega328P. For wireless communication, I used ZigBee at 2.4 GHz. My results were:



In my second version of electronics, I used 868MHz (yes, I'm from Europe) mesh modules from RadioCrafts (they call it TinyMesh). Maximum transmit power is 9dBm. I am testing them last few months and it looks very promising. I am able to communicate for distances over 150 m. Frequencies 868 or 433 MHz are much better in those projects.

The electronics is powered from 2AA batteries via step-up converter. With this, I'm getting quite stable 3 V. Also, I removed RTC and external crystal and for waking up MCU from power-down I'm using watchdog in interrupt mode. Thus, MCU will wake-up every 8s.

Instead of 4 small load cells, I used one 4-wire load cell (LEGO-lars used similar). This is my last problem with this project. The reading from ADC is not stable and it drifts with time. I put 2 kg on my 20kg load cell and after 2 weeks, the readings from ADC were lower then first day. Do you have similar experience with load cell?

Now, last month I am working on 3rd version of electronics. The digital part remains the same, but I completely redesigned analog part. I removed INA125 and used precision opamp MCP6V07 (http://ww1.microchip.com/downloads/en/DeviceDoc/22093b.pdf). They have very low temperature drift and low noise. Instead of internal ADC inside of ATMega, I pick MCP3551 (http://ww1.microchip.com/downloads/en/DeviceDoc/21950b.pdf) -- 22bit sigma-delta, low-speed 13sps. This new version of electronics will contain 2 opamp and 2 ADC, so I'll be able to measure 2 beehives with one electronics.

--------

I am not fan of load cells. I would like to use multi-turn potentiometer. Unfortunately, I'm not mechanical engineer and don't know how to change weight into movement. It would be necessary to use some kind of lever and spring and gears to change small changes in spring into several turn of potentiometer shaft. Not sure if this is doable.

This is my second version of electronics.
(http://uart.cz/wp-content/uploads/2013/12/hive-logger3-11-2013.jpg)
Title: Re: Measuring the weight of a beehive
Post by: Trottel100 on Feb 04, 2014, 07:10 pm
Hi how Long will stay your battery?

From where did you come from (Europe)?

Title: Re: Measuring the weight of a beehive
Post by: vasco-vls on Feb 05, 2014, 10:07 am
Question about battery life is quite difficult to answer. My first version of electronics used ZigBee and step-up converter to 5 V. I was able to run it with 2AA alkaline batteries for 16-20 days, measuring and sending data every 15 minutes.

My second electronics uses different radio and different step-up converter to 3 V. I didn't test this version for longer time than 6 days, but during this time I used fully charged new NiMH batteries and their voltage drop was 100 mV per 6 days, measuring every 5 minutes. So maybe 48-50 days with NiMH batteries? With alkaline batteries, those numbers would be different.

I'm from Czech Republic.
Title: Re: Measuring the weight of a beehive
Post by: Trottel100 on Feb 05, 2014, 06:42 pm
Hi Thank you.

I have build a scale with arduino and 3g shield.
I us a Pb Akkumulator with 7,2Ah. In first time only 3 Weeks, the consumption of the systhem was 60 mA at 12V.
Now the Systhem Needs 5 mA at sleeptime.
I haven´t testet it yet but i think that 2 or 3 month are posible.

Best regards
Title: Re: Measuring the weight of a beehive
Post by: vasco-vls on Feb 06, 2014, 05:53 pm
I don't  have experience with 3G shield for Arduino, but I think GSM modules can draw about 500 to 1000 mA during data transmission. Maybe you can save several measurements in memory and send them later at once. This can safe some power.

If your 3G shield has no sleep mode, try to use power MOSFET to turn it off. This can save a lot of power. ATMega328P in power-down mode draws max. 8 uA (@3V, watchdog enabled). INA125 (or other analog circuitry) can be disabled for most of the time. I think it should be possible to reduce power consumption at sleep mode below 0.5 mA.

Also, try not to use linear voltage regulator (ie. 7805), they are inefficient. Use step-down DC/DC converter (I suppose your accumulator gives 12V) to make 5 or 3 V. Their efficiency is 80 % and more. But remember, you have to choose step-down converter with at least 2A output current, because of your GSM module.
Title: Re: Measuring the weight of a beehive
Post by: Trottel100 on Feb 06, 2014, 09:12 pm
Hi,

yes, i have bought stepdown power suply, this will i test in next time, i turn the 3g modem off and i have disabled the led´s, so it does only Need less than o,1ma.
I stop although the INA 125p.
I think next week i will do the first test.

Now i know that i am on the right way.

I must only work on save data, at time i send every 1 hour one datapackage.

By
.
Title: Re: Measuring the weight of a beehive
Post by: NZbeek on Jun 23, 2014, 08:16 am
Hello everyone, I am a commercial beekeeper from New Zealand. I am an amateur with electronics but would like to work on a project that is practical and that I can use. I can make the physical scales, but I do not know how to make the electronics or write the program. I know how to put electronic components together and can upload a program to an Arduino, can you help with the rest?

Trottel100 your project sounds most like what I would like - a scale that works remotely, I would like to use an Arduino with a GSM shield, this can make one weight recording at the end of each day and send once per day, even once every 2 days is fine. Our hives are a bit heavier, up to 200kg gross. I would like to be able to connect auxiliary hive scale to the master scale to get an average, ideally wireless but wired is not an issue. I would like a long term power source, solar or a 12v sealed acid battery or something along those lines.

If the forum can help suggesting parts, and if there is someone who could provide me the bare bones of the code and walk me through changes, or if there is code that exists I would really appreciate it. I am excited to try and learn something new.

Thanks!
Title: Re: Measuring the weight of a beehive
Post by: GoForSmoke on Jun 23, 2014, 08:37 am
Just a thought.

If you put the hive at one end of a lever on a pivot and the scale at the other then you could by making the lever arms uneven, use a scale rated for much less weight than the hive.

A very precise lever could be very short but practical I think may be 1/2 meter or longer to get 10:1. That way the tolerances of making the lever and positioning points can be cabinetry instead of space rocket.
Title: Re: Measuring the weight of a beehive
Post by: Trottel100 on Jun 23, 2014, 08:04 pm
Hello,
the scale runs, in this year i build up a Homepage, where i would schow how to build the scale.

But i think the time i Need to build the Homepage would be the end of this year.

www.imker-stockwaage.de is the Homepage.

Best regards

Achim
Title: Re: Measuring the weight of a beehive
Post by: NZbeek on Jun 24, 2014, 12:38 am
Thanks Achim, I know you may not have time, but do you think you could send me a list of the components you are using and perhaps the code? It might at least give me a starting point. It is winter in New Zealand but I would love to have a couple of prototypes ready for November to test on our hives this summer.

Title: Re: Measuring the weight of a beehive
Post by: NZbeek on Jun 24, 2014, 10:56 am
This may not be the right place to ask - but what is the best board I could use to achieve 1 input (weight reading from the hive from Shear Beam Load Cell), data send via GSM shield and ability to be solar charged? I have looked at the Arduino mini on the understanding that they use much less power however they do not seem to be compatible with standard shields and may not support GSM? All power savings I have seen appear to be for barebones custom boards/breadboards, I am not technical enough to solder a custom board and would rather buy a ready-made but basic board that will support the aforementioned functions.

Are there Arduino clones that support the same form factor for shields, but are configured for low power consumption? If so, what are they?

Thanks in advance
Title: Re: Measuring the weight of a beehive
Post by: GoForSmoke on Jun 24, 2014, 02:28 pm
You program the chip for power consumption by lowering the voltage and speed and/or using sleep mode and/or turning off parts you don't use. AVR chips with P at the end of the name are branded "pico-power" because of power saving options.

GSM and other addons usually require libraries and some RAM. Stack enough up and you will not be looking at the cheapest chips regardless of the board. Chip size is not directly how much power uses either, they sleep about the same and the running power isn't greatly different at the same clock speed.

But since you are looking for ready made software it would be best to get that and the hardware to match.
Other questions, save for if you will have to choose your own and start a development project that can take months.
Title: Re: Measuring the weight of a beehive
Post by: Trottel100 on Jun 24, 2014, 06:14 pm
Hi,
i want only get the information over the Internet side, i have not much time, here is summer and the bees Need time and i have a normal Job, i would look to force the side.

best regards.
Title: Re: Measuring the weight of a beehive
Post by: GoForSmoke on Jun 24, 2014, 07:41 pm
If you don't really need instant information and have someone visit the hives on a regular basis, it would be far easier and cheaper to log your data to an easily swapped SD card. You could probably train a monkey to do it so a student would get it right about half the time.
Title: Re: Measuring the weight of a beehive
Post by: Clemens on Jun 25, 2014, 12:27 am

This may not be the right place to ask - but what is the best board I could use to achieve 1 input (weight reading from the hive from Shear Beam Load Cell), data send via GSM shield and ability to be solar charged? I have looked at the Arduino mini on the understanding that they use much less power however they do not seem to be compatible with standard shields and may not support GSM? All power savings I have seen appear to be for barebones custom boards/breadboards, I am not technical enough to solder a custom board and would rather buy a ready-made but basic board that will support the aforementioned functions.

Are there Arduino clones that support the same form factor for shields, but are configured for low power consumption? If so, what are they?


I think you do not need a board with a standard form factor for shields because there are no shields you will use. ;-)

The best hardware solution--without soldering / making the PCB by your own--could be the

and you can use the


for reading the load cell.
Title: Re: Measuring the weight of a beehive
Post by: NZbeek on Jun 25, 2014, 10:18 am
Thanks a lot for the reply Clemens, what is the other benefit of the Seeduino over Arduino Uno for example apart from being 'plug and play'?

I had been thinking of the following.

Arduino Uno with Power Saving library by Rocket Scream (found this at comoyo.github m2m adventures measuring temperature of water and air, this seems to be in line with my project except I will record weight) Nick Gammon appears to offer other techniques to save power but it is too complex for me, so unless I need greater power reductions I won't go down that path. Hopefully a solar trickle charged battery that powers the Arduino, suggestions?

I will use this shear beam load cell http://www.ebay.com/itm/371036128442?var=640213319397&ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649
I know people talk about creep, temperature compensation and distortion due to long term loading on load cells. Can you offer advice on this particular cell? It has specs on the page but I don't know how to interpret, it talks about creep and temperature, are those figures ones I will need to use for calibrating or does it mean within those ranges, temperature for example, the load cell will be accurate?

I had intended to use one of the following MCP3551, ADS1231 (I think you used this Clemens) or INA125P - can you help tell me the difference between these, if any?! So far I am leaning towards 1 of the MCP or INA only because I have seen others use it so should be able to wire it up OK. Any advice here?

Finally, the most expensive part is a GSM shield, I haven't decided on what one yet, but hopefully can adapt the code M2M used for sending the data and I will use something like xively.com to store and present data (unless there is another suggestion here too?). Haven't looked too closely yet but there seems to be good information at cerulean.com and liubo.us on load cells and arduinos.

The way I would like it to work is for the weight to be recorded every hour between 5am and 7pm but to only send the data once at say 8pm, if it is too difficult to do an hourly reading and to send  then one reading at 8pm is fine.

I have lots of good references, can I just put libraries/code all together? Or will it be far more complicated. Are there any obvious problems with what I have outlined? What is the best way to start?

Thanks all, sorry for the long winded post!
Title: Re: Measuring the weight of a beehive
Post by: NZbeek on Jun 25, 2014, 11:32 am
Also (just making the most of the time difference) - instead of using watchdog which only allows an 8s sleep, would it be better using a real time clock to sleep it for the 1 hour? - assume this would be more energy efficient.

I thought I would use a 12v sealed lead/acid battery - would it be likely that I would even need to trickle charge by solar if the scales were only being used for maximum 4 months? - more likely 2 - 3 months. I realise that the on board voltage regulator on the UNO will 'discharge' any additional energy supplied, can anyone suggest the best external voltage regulation? - presume I would only need to use a step down regulator, but perhaps there is a switching regulator available that could switch up or down as needed?

If i can find answers to even half of my questions I will be doing well!

Thanks all
Title: Re: Measuring the weight of a beehive
Post by: GoForSmoke on Jun 25, 2014, 04:45 pm
Big enough battery, you could run the rig for a year as long as it didn't have to keep itself warm too.

Do you leave the hives unvisited for 4 months? Could you top up a smaller battery from the electrical system of a small vehicle once in a while? Solar panels might need occasional cleaning from pollen or bird droppings or who knows until it happens over months of time, but hey they are used and do work to power a LOT more than you need.

That's why I say, if you have someone checking the hives regularly, you could save out the whole GSM thing for less than $10 a unit.
It's not just the money either. GSM raises power requirements and adds a lot to the software. What happens if ET calls home and no one answers? ET has to be able to call again, with the data, until that job is done. Just being able to make the call means a library or more to fit in. That's already been done elsewhere, it's possible, but not a complete no-brainer if you're doing your own custom project -- just some non-trivial thing more.

Is there some golden moment that if you catch in a day or week to be on the scene will pay for the extras?

BTW, from news I see we have Japanese wasps killing hives here. Are the wasps enough bigger that a screen could lets bees through but not wasps and would the bees navigate such a screen? People here make bird houses with small holes just to keep bigger birds from robbing bluebird nests as bluebirds eat mosquitos. A fine wire mesh might do the same for bees.
Title: Re: Measuring the weight of a beehive
Post by: Chagrin on Jun 25, 2014, 05:23 pm
Grumpy Mike wrote the RadioHead (http://www.airspayce.com/mikem/arduino/RadioHead/) library which would let you set up a low cost mesh. Aside from your "manager" nodes I would imagine that you would be able to power most of your hives with an inexpensive solar panel and small battery -- using the Arduino itself to do simple charge management.

With respect to the load cell you select make sure you have a credible way to mount it. A shear beam cell with a single point of contact wouldn't be practical unless you had the hive mounted on a pivot. Also, shear beam cells need rock-steady mount points (steel/concrete); if you try to screw the fixed end into wood I would expect it to start pulling its screws out and thus require constant recalibration. As an alternative you can get three-wire load cells (https://www.sparkfun.com/products/10245) (cheaper on eBay) like those that are used in bathroom scales, mount them in the corners of the hive, and would be able to wire the four of them together into a full bridge for a more practical mounting solution.
Title: Re: Measuring the weight of a beehive
Post by: NZbeek on Jun 25, 2014, 10:48 pm
I had thought that the load cells as used in bathroom scales suffered more from the effect of creep and distortion?

The frame for mounting will be stainless steel. Again, to visit some of these hives means a 5 hr return journey, the hives at times will be left for a fortnight, but if the honey starts to flow heavily in that period then a revisit to super sooner will mean more honey collected in a box that we can more easily harvest (rather than the bees packing it down in their brood boxes).

I am not familiar with the Japanese wasp, in New Zealand we have German wasps, which can be a problem. Generally entrance guards, which reduce the size of the hive entrances, are sufficient but still requires a strong hive for defence. If there is a size diffence then certainly this could work - size is the principle for keeping queens out of honey supers, it is also used in pollen trapping where the bee can fit through but not the pollen grains on its legs.

Can i expect issues using the HX711 premounted? - it was suggested to me that it might be more temperature sensitive than other chips like those I mentioned??
Title: Re: Measuring the weight of a beehive
Post by: Clemens on Jun 26, 2014, 12:08 am

Thanks a lot for the reply Clemens, what is the other benefit of the Seeduino over Arduino Uno for example apart from being 'plug and play'?


34.5 mA.(see "Baseline-Arduino Uno" http://www.gammon.com.au/forum/?id=11497 ) vs.  600 uA (http://www.seeedstudio.com/forum/viewtopic.php?f=16&t=3911) plus you have RTC, SD card, solar charger circuit, bee socket

Quote
Arduino Uno with Power Saving library by Rocket Scream (found this at comoyo.github m2m adventures measuring temperature of water and air, this seems to be in line with my project except I will record weight) Nick Gammon appears to offer other techniques to save power but it is too complex for me, so unless I need greater power reductions I won't go down that path. Hopefully a solar trickle charged battery that powers the Arduino, suggestions?


LowPower lib makes more or less the same as described in Nick Gammon article. Consider to use Narcoleptic lib if you will use time information (e.g. without RTC) it recalculates millis for more accuracy but use the right version, see http://forum.arduino.cc/index.php?topic=121096.msg1768493#msg1768493 . About the charging approach have a look at the Seeeduino Stalker  spec http://www.seeedstudio.com/wiki/Seeeduino_Stalker_v2.3 be aware that it is the "Stalker" not an other Arduino clone from Seeeduino.

The most load cells are temperature compensated, I don't know how problematic creep is. For the accuracy we need to measure hive weight is seems to be not problematic. But please read the whole thread there are useful information and a hint to use not 3 wire load cells.  

Quote
I had intended to use one of the following MCP3551, ADS1231 (I think you used this Clemens) or INA125P - can you help tell me the difference between these, if any?! So far I am leaning towards 1 of the MCP or INA only because I have seen others use it so should be able to wire it up OK. Any advice here?


Be aware that these are different ICs the INA is an OpAmp while the ADS and the HX711 has a gain amplifier but also a ADC with a higher resolution than the Arduino's internal ADC (10 vs. 24 bit). But read the post from Lars in this thread http://forum.arduino.cc/index.php?topic=113534.msg1173511#msg1173511 about using oversampling to reach 12 bit in case you will an OpAmp only.

Quote
Also (just making the most of the time difference) - instead of using watchdog which only allows an 8s sleep, would it be better using a real time clock to sleep it for the 1 hour? - assume this would be more energy efficient.


The 8 vs. 60 x 60 sec seems not to be that problem if you have the right board, see http://lowpowerlab.com/blog/2012/12/24/moteino-coin-cell-battery-tests/ how about 3 years with a 2 x AAA pack? ;-)
Title: Re: Measuring the weight of a beehive
Post by: Clemens on Jun 26, 2014, 12:33 am
The frame for mounting will be stainless steel.


Seems to be a good decision if you have the ability to weld it. You can have a look at the professional hive scales like this one: http://www.beewatch.biz/index.php/stockwaage-41.html It is also possible to use two alloy plates like this http://www.emsystech.de/wp-content/gallery/penso/penso-flex.jpg and mount a case on it http://www.emsystech.de/wp-content/gallery/penso/penso-flex-beispiel.jpg. But I think the best mechanical and easiest way is to use the load cell only on one side as Lars did http://forum.arduino.cc/index.php?topic=113534.msg1473176#msg1473176 and take the load twice.
Title: Re: Measuring the weight of a beehive
Post by: Chagrin on Jun 26, 2014, 02:02 am
The most load cells are temperature compensated, I don't know how problematic creep is. For the accuracy we need to measure hive weight is seems to be not problematic. But please read the whole thread there are useful information and a hint to use not 3 wire load cells.


If you're talking about "creep" due to changes in temperature, yes, a three-wire load cell used singly will not be accurate. When you use them in pairs, however, the temperature effects are equal within each three-wire load cell, the change in resistance in the strain gauges will be cancelled out, and the "creep" isn't an issue -- or at least no different than a four-wire load cell.
Title: Re: Measuring the weight of a beehive
Post by: NZbeek on Jun 26, 2014, 04:21 am
I will research shortly, but I need a bit of a break from all the reading!- are there further power savings on the seeduino via library function? - or is it just so low out of the box that it isn't worth it? Am repairing other honey extraction now for a change.

For load cells I will probably build 2 identical side by side but use the 4 x cheap load cells as used in body weight scales, etc.

I dont think solar charging is going to be a requirement but will deal with it if and when I do, no point going down that path just yet and it seems as though the sealed lead acid will be surplus - just going to need to figure out a good voltage regulator now.

I have bought the HX711 for now, it gives me more flexibility for resolution and will be more straightforward I hope.

I dont see the advantage of using a one side mounted load beam opposed to the double end mounted? The beewatch configuration is exactly how I imagined building mine - with the spread of the "H" platform I would have thought the weight would register fairly accurately on the load beam? - exact weight is less import than weight trend, though an accuracy of +/- say 3kg would be tolerable.
Title: Re: Measuring the weight of a beehive
Post by: NZbeek on Jun 29, 2014, 04:34 am
Also, in this article
http://alanbmitchell.wordpress.com/2011/10/09/design-of-the-extended-battery-life-power-controller-for-the-arduino/

he designs a custom 'power controller' - is this essentially unnecessary if using an RTC module to control power on/off?
Title: Re: Measuring the weight of a beehive
Post by: Gopster on Jul 10, 2014, 12:51 pm
NZBeek I am building a very similar set up to yours. However I will be using 2x 50Kg load cells in a full bridge and a HX711 to measure 1 side of my hive (1/2 of the weight).

I have purchased a DS3231 RTC that has an alarm to wake the arduino, I am assume this will use less power than the 8s sleep cycle. I am hoping that a 3600mAh Lithium battery will be enough to upload twice a day for a couple of months.

I am still waiting on the components to come from China. I think my code will be based on this http://arduino.cc/en/Tutorial/GSMExamplesXivelyClient or possibly the water temp sensor you mentioned earlier.

If i was to use the GSM example code could I just add the hx711 library, set the pin and configure the scale in the setup, then add this in the loop?
Code: [Select]
scale.power_up();
  int sensorReading =(scale.read_average(5));   
scale.power_down();


As an int will it be rounded to the nearest kg?

Sorry so many questions its just taking so long for things to arrive from China
Title: Re: Measuring the weight of a beehive
Post by: NZbeek on Jul 11, 2014, 12:10 pm
Great questions gopster, unfortunately I am too much of a newb to answer. I have similar questions though, maybe some one else  on this forum could come up with some suggestions? It might be useful to post your Proposed code?

Bump
Title: Re: Measuring the weight of a beehive
Post by: Gert_O on Aug 20, 2014, 09:25 pm
Pictures of my DIY low profile beehive, prototype. For inspiration
https://www.dropbox.com/sh/0idzsdf4dc6vw4h/AAA-4wGEl7ZlYfUeIJx4jRLFa (https://www.dropbox.com/sh/0idzsdf4dc6vw4h/AAA-4wGEl7ZlYfUeIJx4jRLFa)
Title: Re: Measuring the weight of a beehive
Post by: Clemens on Sep 17, 2014, 09:51 pm

Pictures of my DIY low profile beehive, prototype. For inspiration
https://www.dropbox.com/sh/0idzsdf4dc6vw4h/AAA-4wGEl7ZlYfUeIJx4jRLFa (https://www.dropbox.com/sh/0idzsdf4dc6vw4h/AAA-4wGEl7ZlYfUeIJx4jRLFa)


Hi Gert, good idea to use a checker plate as scale top. I have seen a similar solution in a YouTube video for a scale with much less weight than a bee hive, is it working for about 100 kg? You have two different versions in your gallery. Which is your prefered one? And are two screws sufficient for the load?
Title: Re: Measuring the weight of a beehive
Post by: DaveEvans on Sep 25, 2014, 07:32 am

Also (just making the most of the time difference) - instead of using watchdog which only allows an 8s sleep, would it be better using a real time clock to sleep it for the 1 hour? - assume this would be more energy efficient.

(deleted stuff...)

Thanks all


if you want more than 8 seconds using the watchdog, you can use the code I wrote here:

http://forum.arduino.cc/index.php?topic=248263.msg1774201#msg1774201 (http://forum.arduino.cc/index.php?topic=248263.msg1774201#msg1774201)
Title: Re: Measuring the weight of a beehive
Post by: Gert_O on Sep 29, 2014, 11:00 pm
Hi Clemens - The little red weight (27 x 27 cm) is just made for testing and calibrating the software (indoors beside my wrighting-desk). The grey weight vas made for my beehive. I use a single beam loadcell rated for 150 kg.  I'm not sure that the two screws are sufficient, but as you can see on the foto there is just two holes in the loadcell. I have to test it.
I tried to make a low-profile weight, but it's not stabel enough, so a have to make another platform.
I'm so lucky that my neighbour is a plummer with a workshop and lots of tools i can use.
Title: Re: Measuring the weight of a beehive
Post by: KenF on Sep 30, 2014, 01:02 am
first imagine an upturned box that is big enough for your beehive to sit on.  (say about 8 inches tall).

Now sitting on top of this box is a platform that overhangs the box by quite a reasonable extent (maybe a couple of feet).

This platform is then attached to the edge of the box by means of hinges.  So if you were to stand on the platform and walk past that pivot point, it would tip.

Underneath the platform (on the far side to the hinges) is a microswitch that will detect when the platform is tipped.

You can now place your beehive on the platform over the box.

In the meantime, underneath that overhang is a very heavy weight. This heavy weight is suspended beneath the overhang on a runner.  It can also be moved towards or away from the pivot point by means of a lead screw.

So all the arduino needs to do when it takes a measurement is draw the weight all the way in unitl it finds the end stop.  Then slowly move the weight (by turning the lead screw) until it detects that the microswitch has been tripped.

From calibrations carried out before you deploy this gizmo you can then use a lookup table to see what weight that distance implys.

Naturally, you could have a saftey catch to prevent the platform rising any more than a couple of millimetres, so there's no danger of the beehive ever being tossed off.

If you like I could probably knock up a diagram in paint to explain better.
Title: Re: Measuring the weight of a beehive
Post by: KenF on Sep 30, 2014, 01:44 am
OK I decided to go ahead and draw the thing.
(http://s1.postimg.org/pr4uths2n/hive_Scale.jpg)

So the idea is. When a measurement needs to be made, the arduino will spin the motor up to make sure the counterweight is all the way in to it's home position.

It will then slowly move the counterweight away from the pivot until it detects that the platform has lifted on the far side.
The distance it has moved the weight will be able to be used to assess the weight of the hive on top.

Oh I've just noticed that I didn't label the hinge (it's that blue blob near the counter weight.  It's this hinge that allows the platform to tip when the counterweight is moved away from it.
Title: Re: Measuring the weight of a beehive
Post by: GoForSmoke on Sep 30, 2014, 05:52 am
Microswitches do tend to wear out, I have a collection of dead computer mice to attest the fact.

You might take a look at light interrupt though a led as light source has a finite life even only lit during measure.
You might take a look at piezo disks as touch sensors, the sensitivity can be varied and the life is very long.
You might look into some form of capacitance sensor also with a very long lifetime and can be made really cheap.

I had mentioned putting the hive on a counter balance just to reduce the load cell required, months ago.
It's nice to see some physics used to engineer the parts needs down but running a motor will up power requirements.
Title: Re: Measuring the weight of a beehive
Post by: KenF on Sep 30, 2014, 06:11 am
Quote
Microswitches do tend to wear out
a magnet and a reed switch would do the job nicely.
Title: Re: Measuring the weight of a beehive
Post by: KenF on Sep 30, 2014, 06:17 am
As an alternative to the weight on a motor, you could have a tank that fills with water sitting on top of the platform.  Then all you need to do to trip it is open a valve (that allows water from a separate reservoir) to add more water.  When it starts to tip, the level guage is read.  A separate valve could also be opened to allow water to drain back out.

The reservoir could collect rain water to keep it topped up.
Title: Re: Measuring the weight of a beehive
Post by: GoForSmoke on Sep 30, 2014, 07:42 am

Quote
Microswitches do tend to wear out
a magnet and a reed switch would do the job nicely.


A reed switch will trip over a range of distance, much less tunable than capacitance or piezo touch.
Capacitance is still not as good as physical touch or light interrupt can be.
Piezo can tell how hard is the touch.

I am a fan of piezo disks after experimenting with them. There are cheap ones that work just fine as buttons.
They don't need debounce, give pressure data and can take a good bang. I got 100 for just over $10.
Downside is they need other components to work as I did. I used diodes, transistors and resistors.
Title: Re: Measuring the weight of a beehive
Post by: paysan on Nov 11, 2014, 02:20 pm
Hi Lars, I'm doing a similar project.

I bought a simple bathroom scale.
Removed the 4 sensors en mounted them on a board of wheaterproof pliwood.
On top of that is my beehive.
This 4 sensors to the INA125  and to the Arduino.

Also I installes a humidity and temperature sensor in the beehive.
Future expansion is a counter to measure the activity at the gate of the beehive.


From the arduino a WiFi module to my home network.

http://www.ebay.com/itm/171495443192?_trksid=p2060778.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

I have to do this 20 times. Me and my friend we have 2 times 10 beehives.

The final goal is to publish the weight results into HTML to be viewed in graphs everywhere I am.

So how far are you in the meantime?

Regards, Wim


Title: Re: Measuring the weight of a beehive
Post by: Alain69 on Nov 12, 2014, 11:03 am
Hi Wim / Paysan,

I work in electronic and have also beekeeping as hobby. This project is very interesting: great job realized.
I have just a few questions:

Have you thought about using pessure sensor as MPX5100 to measure hive weight: using simple smooth hydraulically linked containers placed on 4 corners's hive? Preesure is then, function of weight.

About battery, why don't you use a lithium battery size D: it's what is used in industry for GPRS system, which is adapted to Temperature, long life duty and high current need for GPS?


Could you please share your realisation (schematics, ref for OTS parts and SW code)?

Thanks and regards

Alain
Title: Re: Measuring the weight of a beehive
Post by: Gert_O on Nov 21, 2014, 08:14 pm
Thanks for all the diffrent suggestions. But i still think, why get it so complicated when it can be done simple. hydraulically, mecanically etc.

I use a single beam Loadcell (8 $ each (when bying 10 pcs)) and a cheap ( <5$ ) HX711 Dual-Channel Weighing Sensor Module.

And it Works.
Title: Re: Measuring the weight of a beehive
Post by: bboris on Nov 28, 2014, 11:44 pm
Hi
i working on similar project,i made scale for my beehive.I use arduino uno r3,gprs gsm shield sim 900,7.4V 1000mah lipo batery,DS1302 Real Time Clock,HX711 24 Precision AD Module Pressure Sensor Module Weighting Sensor, DHT-11 Digital Temperature and Humidity Sensor,and four cels from home body scale.
 two times in day i recive sms with weight,humidity and temperature.i nead resolve problem with batery,does someone know how i can recive in sms how much i have power in batery,or alarm whan i hawe low power?
thank you for any help?
if you want i can post picture of my prototipe!
Title: Re: Measuring the weight of a beehive
Post by: TomGeorge on Nov 29, 2014, 03:28 am
Hi, KenF, I love it, a work of art, you could sit and watch it weight all day.


It would be a great educational tool to teach these hi-teched kids these days, that a controller and programiing and some HeathRobinson (not sure of US equivalent, I know Art Goldberg, new knew the Mythbusters would eventually help my edjamacation) can do.

Rather than just poke a iphone at it and get google to come up with the answer.

Tom.... :)
Title: Re: Measuring the weight of a beehive
Post by: KenF on Nov 29, 2014, 03:55 am
Hi, KenF, I love it, a work of art, you could sit and watch it weight all day.
Thanks :)
Title: Re: Measuring the weight of a beehive
Post by: Gert_O on Dec 05, 2014, 09:17 pm
Hi bboris
Try to look at this genius piece of hardware:
https://www.tindie.com/products/Dead_Bug_Prototypes/extreme-low-power-data-logging-shield-for-arduino/
It is based on the RTC DS1337 with a smart power-down function (or sleep-function)
Title: Re: Measuring the weight of a beehive
Post by: NielsHolst on Dec 06, 2014, 06:10 pm
I am on a research team doing exactly that: We have put several bee hives on load cells to log weight at intervals of 10 min, or even 2 min, for several months. The load cells are expensive (little creep and 20 g precision) and are not an option for you.

My main message is: You should not worry about creep! You are interested in the daily weight gain, so make sure to measure weight at least every midnight. Subtract subsequent midnight readings and you'll achieve accurate measurements of daily weight gain, despite any creep (the creep during 24h is neglible). Add all the daily gains and you have the total amount of honey produced.

Bonus info: If you pile you hives high, wind will catch them and disturb your readings. Second to second weight  readings could change by 1 kg! Therefore, to obtain one good reading, obtain several readings (say, 30 readings at 30s interval) and compute one reading as the average of that. Maybe calculate standard deviation also to get a measure how precise your average is.

Beekeepers all over the world are on to this, mesuring bee hive weight, temperature, rel. humidity, CO2,  sound and vibrations! What this avalanche of data all means, is still an open question, except daily weight gain (or loss), that's easy to interpret and put to use, right?

Good luck,
Niels, Aarhus University, Denmark.
Title: Re: Measuring the weight of a beehive
Post by: Alain69 on Dec 06, 2014, 10:42 pm
Hi All,

Could you please share links to your projects, as I am very interesting to monitor my beehives during this winter ?

Best regards

Alain
Title: Re: Measuring the weight of a beehive
Post by: NielsHolst on Dec 07, 2014, 08:41 pm
Hi Alain,
In winter, if the bees go into hibernation and form a winter cluster, you will find that each hive looses weight at a constant rate. The rate likely depends on the size of the bee colony; it should be roughly proportional to the number of bees. Or, blame my intuition, maybe proportional to the cubic root of the number of bees, since they form a sphere?

A flat-lining behive (rate of weight loss = 0) means the colony is dead.

Snow will interfere with your readings as in this Danish study, where readings with snow cover were left out [https://www.dropbox.com/s/kmwqukorycwz8ca/overvintring.pdf?dl=0]

The figure shows weight drop in two consecutive winters, together with the loss rate (g/day) equal to the slope of each line. There is one line for each hive in both winters.

- Niels.
Title: Re: Measuring the weight of a beehive
Post by: Clemens on Apr 25, 2015, 10:27 pm
In this posting (http://forum.arduino.cc/index.php?topic=113534.msg1473176#msg1473176) Lars showed a photo with pieces of alloy to mount a load cell.

I constructed a low cost variant of a bee scale. The load cell is mounted between two alloy profiles and distance plates. The holes must be drilled very accurate so I use a CNC for this:

(https://scontent-ams3-1.xx.fbcdn.net/hphotos-xat1/v/t1.0-9/10421385_10204255678691851_5471541591579882505_n.jpg?oh=4a65ba80aacae4dc4c845dd97e5c904b&oe=57BF7940)

You can find more photos under: https://www.facebook.com/media/set/... (https://www.facebook.com/media/set/?set=a.10204255675971783.1073741828.1224510416&type=1&l=41802f0fee)
Title: Re: Measuring the weight of a beehive
Post by: Clemens on May 03, 2015, 08:50 pm
Hi Lars, after finishing my prototype I ask myself why your prototype http://bildr.no/view/dUJJYWRC or http://forum.arduino.cc/index.php?topic=113534.msg1473176#msg1473176 looks like it looks. :-) You do not use a whole L-profile at the bottom. You have some gaps right and left on the vertical flank. Is this to mount it on a subbase? How is the load cell mounted on the lower L-profile?

Do you mount the scale on the front or back of the hive? Or left/right? Front vs. back has the disadvantage that weight is not divided equally in the hive. With honey in the back you have always higher load on the back side. If you put it right/left I think this is not so a problem. But mounting on a shorter side is more easy and more practically.
Title: Re: Measuring the weight of a beehive
Post by: Gilligan on Apr 06, 2016, 04:56 am
Digging this guy up from the dead.

Where is everyone on this project?
Title: Re: Measuring the weight of a beehive
Post by: Clemens on Apr 06, 2016, 02:13 pm
Where is everyone on this project?
I have different prototypes running:

- Weight Platform Prototype I (https://www.facebook.com/media/set/?set=a.10201453236152539.1073741827.1224510416&type=1&l=bca3f242ae) with Film Coated Plywood
- Weight Platform Prototype II (https://www.facebook.com/media/set/?set=a.10204255675971783.1073741828.1224510416&type=1&l=41802f0fee) low cost module, weights only one side of the hive
- Shields (https://www.facebook.com/media/set/?set=a.10204755929557810.1073741829.1224510416&type=1&l=0dd2f9ab84) for Seeeduino Stalker (3.3 V) or Arduino Pro (3.3 V without RTC) and Yun / Uno (5 V)
- a prototype with an ESP8266 on a breadboard
- and also a prototype version with an Arduion Pro Mini and GSM

With the Seeduino Stalker and Arduino Pro as node I can use radio (RFM69) for data transfer, gateway is an Arduino Yun. I used this lib for RFM69: https://github.com/LowPowerLab/RFM69

The ESP uses Wifi and I can send the datasets via REST or via MQTT. Tested with the libs for Adafruit IO: https://github.com/adafruit/Adafruit_MQTT_Library and https://github.com/adafruit/Adafruit_IO_Arduino

I have also a Seeduino Stalker version with a GPRSbee, this sends the data via GSM/GPRS to a PHP script. Data visualization is done by Dygraphs http://dygraphs.com/ There is alos a GPRSbee lib for MQTT so switching from HTTP to MQTT should be possible easily (not tested yet).

We have also a Berlin (Germany) based group that develops a much more elaborated backend for bee monitoring purpose under the project name hiveeyes (https://swarm.hiveeyes.org/docs/)
It is based on BERadio (https://hiveeyes.org/docs/beradio/), Kotori (https://isarengineering.de/docs/kotori/about.html) and Grafana (http://grafana.org/) mainly.
Title: Re: Measuring the weight of a beehive
Post by: NZbeek on Jun 17, 2016, 10:58 am
HI Clemens. Will you be making you prototypes available to replicate? - I am trying a similar project. Just wanting to be able to able to send weight via gsm and have it plotted on  a graph. I will probably have 12 scales in different regions in NZ.
Thanks!
Title: Re: Measuring the weight of a beehive
Post by: Clemens on Jun 18, 2016, 11:12 pm
Yes, I will publish code and constructions files. I am in a beta / alpha phase so not all is perfect, e.g. I have an design error in the PCB file, so I have to connect two pins to the Stalker directly and not over the shield. But one prototype with 2 DHT22 or 33 sensors, 5 DS18B20 and load cell is sending data every 20 minutes since over four weeks without any problem from my balcony. We set up an other installation some days ago with reduced sensors--only humidity/temperature outside and the weight--and this is running also.

You can find the graph of a test installation under
http://open-hive.org/prototype-bee-scale/prototype-brandenburg.html

It is an interactive graph. You can select an area with the mouse--the timeline or the value range--so you can zoom in. With a double click you got back to all datapoints: Under the graph there are check boxes for every data series. If one chosen, for example only the weight and all other off, the script scales automatically the graphic so that the current values are populate the full scale range.

(http://open-hive.org/pictures/prototypes/brandenburg/prototype-brandenburg_screenshot-graph_1.png)

I use dygraphs http://dygraphs.com for visualization, a JavaScript library that deals with many data points. It runs as browser side JS, not on the server Thus, the first call may take more time when thousands records are loaded but if you then zoom in or out is the super fast.

The raw data, which the script directly processes, are simple comma-delimited values on the server:


Date/Time,Weight,Outside Temperature,Outside Humidity,Voltage
2016/06/15 20:34:38,  71.892, 17.3, 99.9, 4.08
2016/06/15 21:34:38,  71.810, 17.2, 99.9, 4.07
2016/06/15 22:34:38,  71.692, 16.3, 99.9, 4.07
2016/06/15 23:34:38,  71.614, 16.0, 99.9, 4.07
2016/06/16 01:34:38,  71.525, 15.4, 99.9, 4.06
2016/06/16 02:34:38,  71.470, 15.0, 99.9, 4.06
2016/06/16 03:34:38,  71.405, 14.0, 99.9, 4.06
2016/06/16 04:34:38,  71.363, 13.5, 99.9, 4.06
2016/06/16 05:34:38,  71.329, 13.3, 99.9, 4.05
2016/06/16 06:34:38,  71.378, 14.6, 99.9, 4.06
2016/06/16 07:34:38,  71.439, 22.0, 78.6, 4.08
2016/06/16 08:34:38,  71.496, 21.6, 71.1, 4.11
2016/06/16 09:34:38,  71.339, 21.9, 76.0, 4.14
2016/06/16 10:34:38,  71.216, 21.4, 73.9, 4.17
2016/06/16 11:34:38,  71.252, 22.0, 75.0, 4.18
2016/06/16 12:34:38,  71.245, 22.5, 64.6, 4.18



You can see on the first photo the complete bee monitoring system:


All sensors are connected with round cables, which can be good passed through the screwable, waterproof cable glands on the case. An exception is the temperature array for inside (on top of the photo). There is a small board as flat cable connector. With this flat cable it is very easy to connect a pin header as as branch for the various temperature sensors between the combs.

(http://open-hive.org/pictures/prototypes/open-hive-system-1/open-hive_bee-monitoring-system.jpg)


The electronic case with a small solar cell under the transparent acrylic cover. The box is waterproof. The screws started after a wet day to rust. The box in the photo is on the balcony for about a month.

(http://open-hive.org/pictures/prototypes/open-hive-system-1/open-hive_box-waterproof.jpg)


Inside the box it's quite busy:

   

(http://open-hive.org/pictures/prototypes/open-hive-system-1/open-hive_box-with-electronics.jpg)


Soem close ups Lipo, printed antenna, DHT on a smal breakout so that it fits in a curler, same DHT covered by a drilled Ikea cup for weather protection:

(http://open-hive.org/pictures/prototypes/open-hive-system-1/open-hive_lipo-battery_and_gsm-antenna.jpg)

(http://open-hive.org/pictures/prototypes/open-hive-system-1/open-hive_sensor-inside-humidity-temp.jpg)

(http://open-hive.org/pictures/prototypes/open-hive-system-1/open-hive_sensor-outside-humidity-temp.jpg)


Title: Re: Measuring the weight of a beehive
Post by: gpsmikey on Jun 18, 2016, 11:23 pm
And I thought we were high tech when we would go out and lift each side of our hives with a fishing scale to see what they weighed !  The one thing we really had to watch for was that they had enough going into winter and in the spring, that they didn't go empty (the Seattle area is notorious for 2-3 weeks of nice weather in April which gets them all cranked up, the queen laying then 2-3 weeks of cold/rain/snow).  You could lose a hive easily in late spring when that happened (cold / rain was also typically when your new queens arrived in the mail with no way to put them in the hives  :smiley-confuse:  )
Title: Re: Measuring the weight of a beehive
Post by: Clemens on Jun 20, 2016, 11:55 pm
[...] and lift each side of our hives with a fishing scale to see what they weighed !
There are a lot of commercial scales out that count on a double "H" as scale frame. The load cell is mounted on the "-" of the "H", see e.g. http://beewatch.de/waagen/stockwaagen/ . I've seen also some DIY prototypes of this scale type. Most wiggly but I don't know is it due to the concept at all or is it the amateur welding skills or the weak and too thin material.

Nevertheless I decided to count on a single side weighting process. Construction is easy, hive stands still stable, and of cause it is cheaper than a full-blown H frame.

I did some control measurement (Herold Magazin with Zander frames similar to a Langstroth Hive) last autumn--I did not write numbers down--but I had maximum 2 kg difference between the front and the back side of a hive.

What are your experiences, do you think a single side measurement (on the back) is sufficient? I asked in a German beekeeper discussion forum and most voted for a compete weighting procedure.
Title: Re: Measuring the weight of a beehive
Post by: gpsmikey on Jun 21, 2016, 12:42 am
We were not that concerned with the accuracy as we were with making sure they were at least 80 pounds or more going into winter (pref. over 100) and they did not drop below about 35-40 in the spring to avoid them starving out.  It doesn't surprise me you get different readings depending on the side - I would think the side with the most sun would be the heaviest, but I never actually checked them that way (and this was before all the problems with colony collapse we are seeing these days). 
Title: Re: Measuring the weight of a beehive
Post by: igorstelmastchuk on Sep 27, 2016, 08:59 pm
Hi,

It's my first post but I have been watching the progress of Lars project.
So let's go:

I have a similar situation with the beehives.
I want to monitor the weight of a freezer full of product to see if it is getting empty (when it becomes light), to send more products without the need to send someone to check.

This could also serve to warn about an interruption in the supply of freezer energy, so I could check what happened before the melting of the products. :D

I was thinking of installing the weight ranges between the wheels and the base of the freezer and a system that would send daily (or on demand) weight measurements by sms.
Energy would be no problem because the system could be connected to power supply of freezer.

Is there any practical and feasible way to test this idea?

I appreciate any consideration. ;)

(https://i.imgsafe.org/ac163a04c0.jpg)
Title: Re: Measuring the weight of a beehive
Post by: blimpyway on Sep 27, 2016, 09:25 pm
One problem with strain gauge between wheel and freezer is that when you move it a little bump on the floor will have a stress/impact far greater than normal load. Strain gauges usually resist 150-200% stress of their nominal measuring force limit, but more than that will very likely affect their readings.
I would use a fixed weight-measuring frame with screws to lift the fridge a few mm once it is in its place.
Title: Re: Measuring the weight of a beehive
Post by: igorstelmastchuk on Oct 04, 2016, 02:15 am
Very good idea Blimpyway.
Can you tell me how can I connect the weight scale sensor with a gsm data logger (data logger model/ what I have to check to ensure the weight sensor compatibility)?
Title: Re: Measuring the weight of a beehive
Post by: blimpyway on Oct 04, 2016, 12:56 pm
I'm not sure I understand the question.

You should look into tutorials, examples about how to:
- Connect HX711 (strain gauge sensor) to arduino.
- Connect arduino to a GSM module or modem to send SMS-es

Combine the two in a arduino program that reads weight and sends weight data via SMS

If there-s any chance the freezer be located in a WiFi coverage area, I would use Wifi instead of GSM.
Title: Re: Measuring the weight of a beehive
Post by: Gert_O on Jan 28, 2017, 10:53 pm
Clemens is there a chance that you can find time to make af software version for Stalker V3.1 (DS1337S RTC and GPSBee ) of yours OpenHive ?


Title: Re: Measuring the weight of a beehive
Post by: Bole on Apr 24, 2017, 02:37 pm
Hello Clemens and other guys,

Clemens, I have some questions for you if you can answer please.

I am working on Arduino based bee scale project and I am experiencing some problems with ADC and GSM module interference.
I am using shielded HX711 breakout board and SIM800L module. Everything works ok till SIM800L module starts to communicates with network. When GSM module receives SMS or voice call ADC data become corrupt so weight is not correct. All is powered from 3.7V 4000mAh Li battery. I've tried to power GSM module from other battery but problem still persist. It looks like interference comes from RF side.
I have made dual side PCB (photo attached) with separate ground planes and decoupling for analog, digital and GSM sections but again problem persist. ADC reading is averaged in firmware but it does not helped a lot.
I do not know what else to try.
What about your experience about GSM module and bee hive weight scale?

Sorry for my bad English. :-[
Title: Re: Measuring the weight of a beehive
Post by: Bole on Apr 24, 2017, 02:44 pm
Here is picture...
Title: Re: Measuring the weight of a beehive
Post by: Gert_O on Apr 29, 2017, 09:41 pm
Bole dont you think its because of the unshielded wire from your loadcell ? The wire should be as short as possible, othervise the vill act as "a pickup" for any noise (and the GSM-signal).

Sorry for my bad English. :-[
Title: Re: Measuring the weight of a beehive
Post by: NZbeek on Jun 26, 2017, 12:51 am
Hi all.
Since I last posted I have still been working on my scales but sporadically. I have working code - and it was working well, I thought I had it at the point where I just needed to start tidying it (understatement). I had the scales running for about 1 week continuously, then was out of the country for 3 weeks. On returning I set it up again and without changing the code it returned an error when trying to upload the scale data. I am not too sure why but my best guess is that when I send the USSD to retrieve balance info, the returned message is overflowing the buffer and causing the AT+CIPSEND to fail. I assume that when it was working the message returned from the network provide was less than the 64 bytes and so the error was not occurring...would this make sense as a reason for the error to occur? The reason I know retrieving the balance is what causes the failure is because the upload works without error when I temporarily remove the balance function.

Please advise if best addressed under another thread.

The flow of the code is:
Normal setup
Power SIM900 and connect network
Query current date and time and send to RTC
Set interrupt alarm time depending on current time

Get weight
Get Balance
Get SIM900 IMEI
Upload
Power down
Sleep

wait for interrupt



Int
Serial output:
Code: [Select]

~⸮⸮⸮⸮⸮
RDY

+CFUN: 1

+CPIN: READY

Call Ready

*PSUTTAT+CGATT=1

OK
AT+CSTT="internet"

OK
AT+CIICR

OK
AT+CIFSR

100.104.40.165
AT+CIPSPRT=1

OK
AT+CIPQSEND=0

OK
AT+CLTS=1

OK
AT+CCLK?

+CCLK: "17/06/26,10:04:29+48"

OK
RTC Time: 2000/1/1 0:1:7
Old datetime:  2000/1/1 0:1:8
New datetime:  2017/6/26 10:4:28
A1 Enabled for 4 PM
A1 Enabled for 4 PM in Setup
AT+CIPSHUT

SHUT OK

NORMAL POWER DOWN
<⸮⸮⸮⸮
RDY

+CFUN: 1

+CPIN: READY

*PSUTTZ: 2017, 6, 25,AT+CGATT=1

OK
AT+CSTT="internet"

OK
AT+CIICR

OK
AT+CIFSR

100.102.156.30
AT+CIPSPRT=1

OK
AT+CIPQSEND=0

OK
Weighing Mode Active
ForceValueRaw>
521
 grams>
71
 LoadB>
8000
 ValueA>
490
 ValueB>
3974
 PC>
0
AT+CUSD=1,"*100*1#,15"

OK
check balance string:
20
Second Pass
013949000670615
15
AT+CIPSTART="tcp","sxxxxs.xxxxxxxxxxxxx.co.nz","80"

OK
AT+CIPSEND

ERROR
GET http://sxxxxs.xxxxxxxxxxxxx.co.nz/pass-data?scale_id=013949000670615&weight=71&bal=20 HTTP/1.0



ERROR
AT+CIPCLOSE

CLOSE OK
AT+CIPSHUT

SHUT OK

NORMAL POWER DOWN
A1 Enabled in Loop
Going to Sleep Now



My reponse code (which I think could use significant improvement:
Code: [Select]

void Response()
{
  delay(100);
  while(!GPRS.available());
  if(GPRS.available()){
    while(GPRS.available()){
      Serial.write(GPRS.read());
    }
  }
}


and the balance query code:
Code: [Select]

void Balance(){
  GPRS.println("AT+CUSD=1,\"*100*1#,15\"\r");
  Response();
{
  while(!GPRS.available());
  if(GPRS.available()>0){
    while(GPRS.available()){
      //balance_character = GPRS.read();
      balance_content=GPRS.readString();
     
      int startPos = (balance_content.indexOf("$"));
   
do
{
    if (isdigit(balance_content.charAt(startPos)))
        break;
}
while (++startPos < balance_content.length());

// Then find the index of the last digit   
int endPos = startPos;
do
{
    if (isWhitespace(balance_content.charAt(endPos)))
        break;
}
while (++endPos < balance_content.length());


    bal = balance_content.substring(startPos, endPos);
    bal.trim();
    Serial.println(bal);
    }
  }
 
  GetID();
}
}



 Just to emphasise, the code worked well previously and the only thing I can think changed is the Network response to balance inquiry. What I don't understand is why the CIPSEND fails and I can only assume that when the buffer overflowed it times out the SIM900 "session". I am not a proficient coder. I have written all the code with a lot of trial and error, which I know people wont appreciate - but ultimately I am a beekeeper and truly understanding this language has been beyond me.

Thanks in advance.
Title: Re: Measuring the weight of a beehive
Post by: NZbeek on Jul 04, 2017, 03:18 am
EDIT^

I found a quick solution - but as with all quick solutions it may not be the best. I just terminate the USSD session, as I had suspected it seems to be that the session is remaining open, either waiting for a reply or because I am not managing the buffer input well.

I end the session with

Code: [Select]

GPRS.println("AT+CUSD=2\r");
  Response();


I would really like to improve my code, but as stated I have done my best with the skill level I have - is there somewhere on the forum I could submit my code for critique / improvement? or is this offered as a service?

thanks
Title: Re: Measuring the weight of a beehive
Post by: pierrepoulpe on Dec 22, 2017, 10:23 am
Hello Folks!

With a friend beekeeper, we started to dig the subject a few yars ago.
Like everybody, we started with the cheapest strain gauge we could find. Stability of the measure was disastrous.
We thought about buying better load cell.
But after research, and discussion with another beekeeper who also searched on the subject, and who has a background in physical measurement, came out of these discussions that there were no good tradeoff between price of the components, and quality (especially stability).

So we moved to a completely different approach, which can be much more DIY-friendly than load cells : we built an automated mechanical scale.
Principle is pretty simple, you take a roman scale, a beam, suspend mass to weigh on one side, slide a counterweight the other side, an articulation between, and that's it. Mass to weigh = ratio of the distance  articulation-counterweight / articulation-mass * mass of the counterweight.

Electronically, it becomes very simple, arduino has to drive a stepper motor, and check the status of a sensor (optical, reed..) to detect the balance. No analog layer...

Stability of the measure is dependent on the structural stability of the beam on its length, given there is no constraint on it in the length direction, we could say problem of stability is solved.

The tricky part is now to build something that integrates nicely under a hive.
It's what we worked on.
Quickly, we had prototypes that worked very well.
Then we wanted to make a version that was easy to replicate if we needed to make 10, 20, 30.....
And when we started this "industrialization", we thought about making more and sell it as kit.

Here we are, project is mature enough now :
We release all the sources (mechanic, dedicated board, firmware, cloudware) for DIYers
And for beekeepers who don't have {time/energy/skills} we propose for sale a kit.

If it sounds interesting enough, you may visit our website :
www.openhivescale.org (http://www.openhivescale.org)

And the sources :
https://github.com/openhivescale (https://github.com/openhivescale)

Cheers, Pierre
Title: Re: Measuring the weight of a beehive
Post by: TomGeorge on Dec 22, 2017, 11:38 am
Hi,
Fantastic project... I like the fact that you have discussed the pro and cons of various methods, and your product looks good.
(http://www.openhivescale.org/img/IMGP9335R.jpg)

Tom.. :)
Title: Re: Measuring the weight of a beehive
Post by: pierrepoulpe on Dec 22, 2017, 12:30 pm
Thanks Tom!
I posted here pictures of the previous designs, maybe more adapted to the build of a single scale on your own.

http://www.openhivescale.org/forum/viewtopic.php?id=4 (http://www.openhivescale.org/forum/viewtopic.php?id=4)
Title: Re: Measuring the weight of a beehive
Post by: TomGeorge on Dec 23, 2017, 03:09 am
Hi, mate.
I'm not a beekeeper, but it will be a good source of reference for the number if times that we get questions about weighing beehives.

There must be other applications that a platform like yours can be use for.

Thanks Tom...Merry Christmas
Title: Re: Measuring the weight of a beehive
Post by: Gert_O on Jul 21, 2018, 04:35 pm
My last creation, a 4-point BeeScale. You are velcome to follow my scale on:  http://www.minibier.dk  My scale are named Beder-2.

Update every ½ hour at Sigfox net. Battery last more than a hole year.

https://www.dropbox.com/s/ldk195fgg0p7f5q/DSC_0192.JPG?dl=0
https://www.dropbox.com/s/44455ocnmfuthsi/DSC_0193.JPG?dl=0
https://www.dropbox.com/s/2otgwj1izl4zbw2/IMG_3626.JPG?dl=0
https://www.dropbox.com/s/2sxtvyhxwepx4ok/Beder%201.jpg?dl=0

(Cut and paste too your browser)