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Topic: What Arduino Should I Choose? (Read 460 times) previous topic - next topic

krasher

Hi,
New to the Arduino scene and in need of one for a current project. Based on the criteria below, what would be the most appropriate board for my situation?


    Read data into the device via an external connection (probably a serial string)
    Possibly capture identification information - via keyboard/ bluetooth/ wired reader?
    Allow dosage rate (mL/Kg etc) be set without requiring a new program (ie user interactive)
    Control at least one output - a solenoid valve or pump
    Write a log file containing date (and time), id, weight, dosage
    Interface with the user - i.e. a screen (Computer screen or small touch screen)

Any help would be appreciated
Cheers

Robin2

It would be easier to give advice if you describe the overall project rather than its component parts.

Several aspects of your list would be easier to implement on a RaspberryPi and it is not obvious if any of them could not be done with an RPi.

...R
Two or three hours spent thinking and reading documentation solves most programming problems.

krasher

Hey Robin2,
Concept is animal walks onto scales, and based on the weight of the animal, an accurate pour-on spray dosage is applied to it via a small tank holding the spray and a 12v pump. This pump will pressurize a line with the liquid and ideally a small valve will regulate how much liquid is dispersed based on that original weight. Dosage is like 10ml per 100kg. Hopefully that's understandable

Cheers

Robin2

Thanks. That's a big help.

Based on what you have said in Reply #2 there is a need to detect the weight from the scales, calculate the required dose and open a valve for the time required to administer the dose.

You have listed other things in your Original Post but let's ignore them for the moment.

My assumption is that reading the scales and calculating the dose is straightforward.


Dispensing the dose may not be.

What are the smallest and largest doses that will need to be dispensed and what margin of error in the amount dispensed is acceptable?

And following from that, how long would the valve need to open to dispense the smallest dose?

Have you identified a suitable valve? If so, how would an Arduino control it?



There have been other Threads in which liquids are dispensed using syringes (not necessarily with a needle). It is easy to calculate how far the plunger must be depressed to dispense a specific amount. Of course the inconvenience of a syringe is the need to refill it.


...R
Two or three hours spent thinking and reading documentation solves most programming problems.

krasher

Yeah so what youve said is pretty much exactly it and the main difficulty is opening the valve for a set period of time. The formula that needs to be entered to convert ml to kg is fairly simple to write.

There is also the possibility of the arduino telling the pump how long to stay on for to correctly pressurize the line and then the dose could be administered manually with a handpiece.

There are a few options in terms of configurations and a valve would be optimum but it depends how accurate we can get it.

Minimum dosage would be about 20ml and max 80ml.

Also how possible would it be to change the rate of dosage (say you wanted 20ml per 100kg instead if 10), could that be done with a touch screen?

I havnt looked into valves as of yet as i wanted to really understand whether the arduino could control something like that accurately first, but will look into it.

A manual handpiece would be fairly similar to the syringe concept, just upscaled. The real need is to ensure that the amount of liquid drawn into the 'syringe' is done automatically and administeration can be done manually. A valve would be great but if not accurate within 5 ml not exactly helpful.

Cheers

Robin2

I think you need to figure out your valve before you go any further. One possibility may be to use soft plastic tubing that could be squeezed shut by a servo.

Does the liquid need to be pressurized or would a simple gravity feed be adequate?



You can get small touch screens that work with an Arduino. However you should be aware that the programming for the user interface (whether touch screen or not) will probably take many more lines of code than the part of the program that measures the weight, calculates the dose and dispenses the dose.

Speaking personally I would much prefer to create the user interface using Python and the libraries available for it rather than C++ which is what made me think of a Raspberry Pi. If you are intent on using an Arduino this AWIND library may be of interest. I have not used it myself.

...R
Two or three hours spent thinking and reading documentation solves most programming problems.

krasher

Yeah thanks for that and am looking into valves at the moment. Gravity fed would probably not be ideal as i need quick 'reloading' times if you will.

I am looking into Raspberry Pi's as well and python is still an option as my colleague has a little experience with it. So would Raspberry Pi be a more suitable option, and could i put a screen or touchpad on a Pi?

Cheers

Robin2

Yeah thanks for that and am looking into valves at the moment. Gravity fed would probably not be ideal as i need quick 'reloading' times if you will.
I was thinking of dispensing directly from the gravity tank. If you had (say) 5000ml of liquid in the tank you could dispense a lot of shots without reloading.

IMHO it would be much easier to put a touchscreen or a screen and touchpad on an RPi.

...R
Two or three hours spent thinking and reading documentation solves most programming problems.

krasher

Would you agree with dispensing from a gravity tank whilst still having a solenoid valve  to regulate different dosages based on different weights?

Yeah I'm now thinking RPi as its simple usb connection to a touchpad. Also what are your thoughts on touchpad vs phone as a display and how hard is it to transfer info from RPi to phone. I've seen that latest version of Pi has bluetooth however I'm assuming I would need an app of sorts and is it worth the time and effort?

Cheers

vffgaston

I am looking into Raspberry Pi's as well and python is still an option as my colleague has a little experience with it. So would Raspberry Pi be a more suitable option, and could i put a screen or touchpad on a Pi?

Hi,

Yes, an example:

https://www.amazon.com/Raspberry-Inch-Touch-Screen-Touchscreen/dp/B0776VNW9C

Regards.

krasher

Hi,
Thanks very much for that link. So will that just display any info the Pi receives or is there coding involved in transferring the data?

vffgaston

Hi,
Thanks very much for that link. So will that just display any info the Pi receives or is there coding involved in transferring the data?
Hi,
Well ... The Pi is a very small computer that may receive data in many ways: keyboard, mouse, USB, LAN, serial connection, etcetera. As in any other computer you need some software to display the incoming data: most of the times the OS takes care of that (keyboard, mouse); maybe you need something more elaborate for USB or LAN, it depends of the type of data, where is it coming from ...
Regards

Robin2

Would you agree with dispensing from a gravity tank whilst still having a solenoid valve  to regulate different dosages based on different weights?
I don't understand what was in your mind when you wrote that. I presume you were thinking of something that might not work, but I don't know what.

Have you identified a suitable solenoid valve?

...R
Two or three hours spent thinking and reading documentation solves most programming problems.

krasher

Vffgaston,
Cheers for that was a great help

krasher

Robin2,
What i was thinking was a gravity fed line with a solenoid valve on the end. Then after the solenoid valve is a gun that the user manually distributes the liquid out of. The solenoid valve regulates how much liquid goes into the gun based on the weight then closes so perfect doesage waiting to be distributed. Hopefully thats a bit clearer

Cheers

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