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1  Forum 2005-2010 (read only) / Interfacing / Re: wireless battery powered garden irrigation advice on: April 08, 2010, 03:35:51 pm
@SSzretter  I'm in the same boat.  Right now I'm putting together a garden data collector, and will later try and have it do something useful based on the data (eg water the garden)...

So far, this is what I have sketched out:
  • Basic design is a tupperware on a ~18" piece of 1" PVC which sticks into the ground
  • Coming out of the PVC (this is buried into the ground) are temperature and moisture sensors at different depths
  • Above ground is a temperature sensor, a light sensor and possibly an old anenometer I have from my parent's old weather station

Soil temperature is interesting for several reasons (it tells me very speficially when it is time to plant seeds of different varieties to maximize germination rates).  I saw two main approaches to this, one digital, one analog.  The digital approach is to use something like the quad thermocouple approach
while the analog approach would be to use an AD595.  

A cheaper digital tack (from what I can tell) is to build leads on to multiple DS18S20's.  I think the range and resolution are not as good as the much more expensive thermocouple approach, but I think it's still fine for my purposes.
states that
For getting started, especially if your chip is within 20 feet of your Arduino, the parasitic option is probably fine.
Hopefully if I run copper core ethernet cable down the PVC pipe and stick out the protected sensors at different depths, I should be OK, and only have one ethernet cable for all my temperature probes.
Somewhere I saw a post about waterproofing the sensors by enclosing them in copper tubing...

Somewhat more important is soil moisture, and I was planning on using the recommendations of
either the purchased
or diy varieties

After that (I'm a statistician, so I'm trying to design some data that will have good explanatory power for garden yield, time to maturity, etc) I'm interested in estimating the lumen-hours of light during the day using a CdS, humidity and a couple other things...  I'm not sure yet how best to measure humidity. The only option I found so far was:
and I don't know how it works (eg What part can be exposed out of the weatherproof enclosure the arduino will be in- somehow I'll have a lead that connects to sht15 + something? Any ideas for outdoor use?

I'd like to put it all together with an Xbee or wifi that sends the data to my server which then throws it into a database used for model fitting/calibration.

Does this sound like your project?
2  Forum 2005-2010 (read only) / Interfacing / Re: wireless battery powered garden irrigation advice on: April 08, 2010, 02:05:56 pm
@Dougl - I'm a noob about to try and do something very similar to your setup, but I have a couple of questions...

My first question is: What wattage solar panel should I buy? Do you have any ideas about how the actual wattage produced during a 24 hr day relates to the max output listed on the panel?  This all depends on how many watt hours I expect to use on a daily basis...  I'll try and check out the solenoid data sheet to figure out how they work when I get home from work...

A related question is: Suppose I wanted to measure power use in watts.  Would I need both a multimeter (for voltage) and a clamp meter (for amperage)?

Another related question about 12 V DC (battery) and 24 V AC or DC (out to solenoid) is here if you have some thoughts about that...

All thoughts/opinions welcome...
3  Forum 2005-2010 (read only) / Interfacing / Re: Car Battery to power Arduino Nano on: April 08, 2010, 01:47:28 pm
On a related note (I am a total noob), does anybody have advice for connecting a solar panel to a 12v lead acid car battery?  I have little experience, and in my garden I am planning to have a 12v car battery power both my arduino as well as some 12v lights (for minutes at a time, a couple times a week), and some 24v solenoids to control water flow (and maybe a 12v water pump if I need more water pressure than gravity provides).  I also wanted to put in a solar charger (as having a charged 12v battery around is a handy thing).

Having not smoked any electronics yet, my neanderthal first thought is to clip everything 12v directly to the battery terminals. I read that I needed something to prevent overcharging of the battery.  

I also saw an article about protecting the arduino from excessive voltage/amperage
so I assume I need an inline fuse just in case...

I also plan to have a 12v->24v voltage converter power the solenoids as needed.  I still don't know if it's easier/cost effective to build a voltage converter or to buy one.  I also don't know what kind of relay I need to turn the solenoids off/on...
4  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Android/iProduct app interface with arduino? on: April 15, 2010, 09:17:10 am
Just saw a related post at openPICUS + quadraspace...  An interface that arduinos might implement one day in the future?

The idea is simple (when it's genial it's always simple): create a universal language for sensors and their networks. The Sensor will join the network, it will present itself (my name is, my range is and so on) and all the data are sent to a central processing unit (a lightserver). There's a nice presentation on their website:
Looks like it's in planning/ pre-planning phase...
5  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Android/iProduct app interface with arduino? on: April 13, 2010, 02:08:38 pm
Thx for the update there.  I can't wait to see what products/touch screen products/etc will be on the market at the end of the summer.  Christmas is only 8 months away....  I'm going to have a decision to make...

The archos 5 is a nice piece of hardware.  Too many choices...
6  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Android/iProduct app interface with arduino? on: April 13, 2010, 07:21:13 am
Picked this up on slashdot this morning...

An android based tablet...  That's the kind of setup I'd love to have (android tablet for the UI + arduino, with any kind of bluetooth/wifi/usb connection)....
7  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Android/iProduct app interface with arduino? on: April 09, 2010, 02:03:21 pm
@cr0sh I hear you.  I started with debian 2.0 on a 486 with 24 Mb of ram around 2000...  There's something to be said for experimenting, and there's something to be said for having your phone work when you need it.

Using the default SDK would be really, well,  convenient.  Time...
8  Forum 2005-2010 (read only) / Frequently-Asked Questions / Android/iProduct app interface with arduino? on: April 09, 2010, 09:35:11 am
Hi All,

I'm an applied statistician who is interested in the arduino for data collection.  So I know pretty much nothing about hardware, writing apps, etc.  Does anybody have experience turning an arduino into a glorified sensor for an android/iProduct (ipad, iphone or ipod touch)?  If I can pull data from an arduino into an app, then use a couple of APIs to analyze and vizualize the data, it would be useful.  Small form factor, big api exposure...  

Just thinking out loud- I know it's possible in theory, but has anybody done it?  I imagine it has to do with the SDK of the devices and the types of input they support?  I know that there are microphones, sd card readers and more that plug into the input slots of existing iProducts...

I know it's kind of cheating the arduino by using very little of its potential, but I'm sure you could put custom buttons/wheels/potentiometers/motion sensors, etc on there as well.

Thoughts?  Other posts I should look at?
9  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Have Goal; Need advice to create arduino sensor... on: April 01, 2010, 09:00:15 am
Do you need the Arduino to turn the water on/off, or can that be your host/server?

I'm still trying to figure out what my options are.  I have several hundred gallons of rain water/lake water next to the garden.  So all I need is the smallest of solenoids to control the gravity feed.  Before I was thinking about SSRs (solid state relays), maybe connecting a small pump to my water tank to increase the pressure.  Thoughts on control valves for gravity fed watering or SSR + 120v pump?

failure may have a large impact

Thanks gbulmer.  I hadn't thought too much about the downsides yet...
10  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Have Goal; Need advice to create arduino sensor... on: April 01, 2010, 08:52:18 am
Thank you all for the excellent advice.  My arduino starter kit + extras should be arriving tomorrow from adafruit.  I have gone from zero knowledge to > 0 knowledge in about 10 hours of reading, and found that many of my questions are rather trivial given the right webpage.  The project 1 (temperature + gps data logger) should be straightforward. I'm going to start with a gps + datalogging shield from adafruit, and a basic temperature probe (TMP36).  

My knowledge has increased exponentially since I posted, and here's where my current progress is (current knowledge-wise progress since my arduino hasn't arrived yet and I couldn't find a simulator online in less than 3 min of googling).

As far as the garden arduino (garduino, growduino) project, I found many related projects (links available to anybody interested), with several on, and at least one in the forums here, but none exactly like what I'm going for (I have an outdoor garden, ~2500 square foot garden, and make decisions about planting and watering based on soil temperatures at different depths, soil moisture, weather forecasts, etc)

To measure the temp at different soil depths in my garden, I'm planning to get a quad thermocouple interface (it seems a lot simpler and time saving compared to configuring 3 or 4 thermocouple interfaces myself).
I'm still not 100% sure of the differences between an AD595 and a MAX6675, but it appears to be pins (14 vs smiley-cool, and perhaps one is capable of reading very low temperatures?  I have discovered datasheets, but still haven't figured out what info on them will be most useful, and I haven't started saving/cataloging them either (organization opinions welcome).

There may be better alternatives (cheaper) for reading the temperature ranges in my garden, but I couldn't find anything definitive.  I plan to stick the thermocouple probes out the side of a vertically buried piece of pvc, with the probes at different depths.  The arduino will sit in a weatherproof enclosure on top of the PVC, and I'll run the thermocouple wires up the inside of the pvc.  I like the flashlight/torch idea for the enclosure (thanks HTH/gbulmer).  I'll also use a CdS photocell to measure accumulated sunlight...

As far as soil moisture goes, I'm not sure- I have been focussed on thermocouple stuff because this seemed easier...
seems to be an easy approach (step 4).

As far as getting the temperature data to an external database, I'm still not sure what the best fit is.  The Xbee seems like a great option, and if I have multiple sensors it's even better.  At the moment, I'm still more comfortable with wifi (802.11 rather than 802.15).  It looks like it's not trivial to connect multiple Xbees (or it wasn't at some point in the past) or to create a mesh of them.  I don't recall finding the power usage differences between 802.11 and 802.15. (goal is to have something battery powered, maybe add the adafruit 6v 1.5watt small solar panel later)  Also, I don't know what the price difference would be (for one or two sensors in the garden).  I may go with 802.11, but I need to read more.  On the Xbee upside, I could do some wireless networking with my neighbors  who are about 200m away through somewhat dense forest.

I could always put an Xport and have a solar powered wired-wireless hub in my garden, but that's just asking for problems.

Thanks, Blair
11  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Have Goal; Need advice to create arduino sensor... on: March 31, 2010, 11:29:00 am
Thanks Pauly.  I (back) ordered a started kit from adafruit earlier along with a gps and gps data logger shield and a couple of sensors for temperature, light, etc.  

Sorry to be so clueless about wireless, but how do I receive data from the xbee and get it into python?  I read the description, but it wasn't totally clear if the xbee explorer usb was for programming the xbee or for recieving its transmissions.

Is it

arduino+xbee <--->
12  Forum 2005-2010 (read only) / Frequently-Asked Questions / Have Goal; Need advice to create arduino sensor... on: March 31, 2010, 08:35:10 am
Hi All,

First time poster here.  I'm an applied statistician, primarily interested in arduino for data collection (sensors -> arduino -> server -> database), and secondarily to learn more about microcontrollers/sensors.  Most of my projects are data capture (get data, send it somewhere).  One of the projects is an extension (for my garden- if soil is dry, then water, wait 12 hours, repeat)

I did some research in undergrad using matlab and a breadboard, so I know some basics; worked as a software engineer, so I can set up dev environments, have experience with systems administration.  Hope to use python scripts on my server to capture data from the arduino.

Goals:  Get Projects 1 and 2 working (and start project 2 in a way that it would support the extensions)

Project 1: "Easy" Project- data capture and storage.

Motivation: I'm working on spatiotemporal models of temperature, and I want to collect high spatial resolution temperature data (will go on my bike for my 25 mile commute to work and on the car roof)

Hardware idea: arduino + temperature probe + gps + sd card + battery + LCD + enclosure.

Software: read temp, lat/long, time, write to sdcard.

I read several forum postings, tutorial articles, etc and believe that having a DS18S20 temperature sensor on an arduino should work (but I don't know how to put a lead of an arbitrary length on it).  That seems like the place I'll start (arduino + temperature).  Haven't played with the SDK, but assume that it's pretty easy to do (I have little experience with assembly, but looks like I don't need to know too much?).  Here are some initial questions:
  • What's the difference between an arduino and a freeduino?  
  • How do I count I/O needs?
  • Which arduino model(s) would I want to buy?
  • What would you recommend for a hardware starter kit for these 2 projects (maybe I want a total of 3-5 arduinos at the end of the day?)  Thinking an LCD, some temp sensors, light sensor, maybe sd card shield, maybe wifi unit (shield?), a gps, ... (no idea what accessories I need to connect the sensors to arduinos)  Opinions on online stores?
  • what is a good way to enclose the arduino in a weather proof container? (tupperware with dessicant inside?)

Project 2: Collecting garden data

I want to measure temperature at 3 locations (above ground, 5 cm below ground, 10 cm below ground), light level, humidity if possible (saw something about an SHT-15), and soil moisture (really want to know the resistance of the soil, I have some home made sensors).  I want this to sit in a remote location (my garden), and I don't mind storing data on an SD card, but would prefer to setup a wireless link to an atom server about 100' away. I assume battery power is the best option.  The software side is "simple": read input from sensors, transmit, wait 30 min, repeat.

So the questions here are:
  • what is a good way of putting leads of various lengths on to the temperature sensors to get the sensor to 5 or 10 cm deep?
  • suppose I just want to read and transmit voltage from a circuit (eg I provide thermocouple wire, or I connect it to homemade moisture sensor or to homemade anenometer).  (please correct my abuses of electrical terms- like voltage and circuit if I misuse them)  Hopefully once I crack open the SDK this will become obvious.
  • what is a good way to enclose the arduino in a weather proof container? (tupperware with dessicant inside?)
  • is wireless ready for primetime?  I want to focus on the data analysis, not on arduino troubleshooting.  (I prefer 802.11, but might be able to work with bluetooth?)  I saw some units on sparkfun for $70-90 each... seems pricey.

Project 2 (extension 1)
I have some old weather station parts (anenometer specifically).  I can calibrate it on the server side if I can figure out how to connect it to the arduino.  I don't think it uses any power but that it generates current, creating voltage as it turns?  It's cable to the old weather station looks like a phone line.

Project 2 (future extension)
Ideally I would like to automate my garden watering.  I was motivated by this post
(not allowed to use links on first posts)
Basically the software side would be: at 6am, read moisture levels;  If in range 1, turn on water for k units of time, if in range 2, turn on water for k+1 units of time, etc; (would use weather forecasts in the future...)
  • Any idea what hardware I would use?  I'm assuming some kind of servo/solenoid something?  (No idea where to look to find that kind of thing)
  • Or, is there hardware (diy) to turn a 120v outlet on/off?
  • Suppose I had all that working and still had free time.  Could somebody point me to a way to transmit to the arduino? (say an integer between 1 and 10).  In the networking world, it would be nice to have the arduino query a webserver on my atom server (or any server, or just know to 'listen' every k hours)

Please let me know if you think that another platform would be better suited to either of these projects, but from what I've read, it seems like arduino is the perfect solution- small, low power, flexible, inexpensive, open source, etc.

Thanks in advance for all comments.  I can blog about the process in detail as a way of saying thanks.  

13  Forum 2005-2010 (read only) / Bar Sport / Re: water solenoids? on: April 14, 2010, 07:54:51 am
Thanks so much for the advice- just what I was looking for.  It's going to take me a while to digest all of it...  
14  Forum 2005-2010 (read only) / Bar Sport / Re: water solenoids? on: April 13, 2010, 02:07:31 pm
Thx for the advice.  I am no stranger to dessicant.  I bought some 55 gal plastic barrels from craigslist ($10 each).  I may take one of those, lay it down so it's horizontal at the bottom of my garden bench and make two shelves in it to store things dryly- maybe even put a damp-rid in there...  

Very basic question: Suppose I have two 12v batteries in serial, and I have two 12 v solar panels in serial.  Is there anything I ought to add to the circuit?  Put a fuse in the circuit just in case somebody tries to connect it backwards?

Do you suggest any forums to ask elecrical questions on?

Turns out I bought the 24v ac solenoids instead of the 24v ac/dc ones.  Any thoughts as to whether it's easier to make an inverter (invert from 12v or 24v DC to 24v AC?).  I guess I'm looking for a deep cycle battery... I found a UPS on craigslist- any idea if those batteries would be appropriate for my use?

The solar battery box links were pretty nice.
15  Forum 2005-2010 (read only) / Bar Sport / Re: water solenoids? on: April 13, 2010, 12:37:40 pm
Is there any particular reason you are using a car battery, instead of something like a 12 volt SLA (sealed lead acid) battery?

I have an old car battery that still holds a charge- that's the only reason...  Two batteries in a series sounds like a fine idea (any idea if it's bad form to run both 12v and 24v stuff off of the same battery (the stronger of the two assuming I find another battery?)  The batteries are going to sit in the bottom of a gardening bench/shed, so they'll be dry, but exposed to high humidity...   I have a couple thousand square feet of enclosed garden space, so size isn't a big deal for me...

I was reading somewhere about running batteries in series...  I read something that made me think it was poor form for some reason. (could lead them to "wear" differently)...

I'm still looking for some kind of electrical engineering book (focussed on the math side of things, maybe with sections by component (transistors, capacitors, etc)...  
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