Hi guys, I'm trying to build a system of automatic fish feeder.
This consists of 50 feeders, they would all work synchronous, all at the same time.
I'm a bit lost here. Am I right about thinking the I would need 50 motors (5V)+drivers all connected to one Arduino?
Or do I need to split into multiple mini "systems" using multiple Arduino?
Many thanks for any help, I'm a beginner with stepper motors.
What type of motors? how far away are they from each other and the Arduino? What is the specification of the 'Automatic feeder' e.g. timings, weight of feed, power supply availability? Do they need to be synchronous? Would batches of feeders work better?
A little bit short on detail here.
You refer to steppers, and operating them on 5 V. What steppers are these" (I think I may be able to guess).
Just how will the steppers actually be used?
For such a project, you almost never require more than one Arduino, but we need to have some idea of the distances between the parts.
Paul__B:
A little bit short on detail here.You refer to steppers, and operating them on 5 V. What steppers are these" (I think I may be able to guess).
Just how will the steppers actually be used?
For such a project, you almost never require more than one Arduino, but we need to have some idea of the distances between the parts.
missdrew:
What type of motors? how far away are they from each other and the Arduino? What is the specification of the 'Automatic feeder' e.g. timings, weight of feed, power supply availability? Do they need to be synchronous? Would batches of feeders work better?
Thanks so much for the replies. Sorry for the lack of info.
This is what I was planning to use: https://www.ebay.co.uk/itm/3Pcs-28BYJ-48-DC-5V-Stepper-Motor-ULN2003-Motor-Driver-Board-Kit-For-Arduino-UK/164670375825?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160908105057%26meid%3D1e7f7a436ee44f7c9ce3ee6d813374d6%26pid%3D100675%26rk%3D3%26rkt%3D15%26mehot%3Dnone%26sd%3D293631295327%26itm%3D164670375825%26pmt%3D1%26noa%3D1%26pg%3D2380057%26brand%3DUnbranded&_trksid=p2380057.c100675.m4236&_trkparms=pageci%3A63df609a-9aaf-11eb-aa76-0a08e6f67219|parentrq%3Ac07177bc1780a45c0434e991fff79667|iid%3A1
The motor would complete a full turn in 14 days (If that's possible at all?), one step/day.
The weight of the food is very light, I'm not to worried about that (4-5 grams)
The distance between the feeders is around 1m.
Corrected link(! 
): https://www.ebay.co.uk/itm/3Pcs-28BYJ-48-DC-5V-Stepper-Motor-ULN2003-Motor-Driver-Board-Kit-For-Arduino-UK/164670375825
Right click "View Image" to see what eBay does not want you to see here!
That is exactly what I thought you were proposing to use from your first description. 
Better to buy the motors without the drive boards; you can use TPIC6B595s to control them and probably better, use the 12 V version of the motors. In any case, two per shift register as the register has 8 outputs and each motor requires 4.
Using TPIC6B595s, you can control quite a few with only three Arduino pins. You have the option of paralleling the control signals to the shift registers so that all, or a group of them, move together, or individually controlling them if you need to.
If you only ever drive them in one direction and do not care where each is at any given time, then you do not need a "home" indication so that makes the whole project trivial.
Thanks very much for the suggestion. It all makes sense ( I think 
)
The mechanics of how you are going to drop food it much more important than the motor.
Most 7 day feeders have a pizza disk that lets you have chambers. You can put in the quantity you want for each tank.
each chamber drops it's contents. you rotate it for one chamber. simple with a stepper.
a month feed could be similar with a way to automatically fill the chambers.
the Stepper part with the Arduino is actually the easier part.
one thing you said seemed to indicate you want them all to operate at the same time. Typically, you would do groups so that your power supply is smaller. If it takes 1 minuter per chamber (very slow) you could do 10 at a time and in 5 minutes all your fish would be fed.
Sounds like a pet store, or a fish farm.
If I were designing this I would make each feeder independent with its own ESP connected to a controller using MQTT.
This approach would eliminate running 50 data cables. You would just need to provide power to each station. This could be as easy as a phone charger style of wall-warts. It also has the benefit of flexibility where you can easily add or remove feeder units.
For 50 units I would be tempted to design a PCB.
Fifty units on one Arduino sounds like some long wire runs and fifty Arduinos needsa lot of power outlets. I'd be inclined to do it SteveMann's way but make each station service multiple tanks, just not fifty. Five each maybe. Depends how the tanks are physically located.
simple rule of the forum.
the amount of speculation is inversely proportional to project information.
I am also on-board with Steve for fish farm use at least. some tanks can be 50 meters wide
for a fish store, it would be a simple matter to run the cables as you would have multiple rows of tanks a meter or less apart.
I would not use steppers motors but a normal gear dc motor and have some form if basic position encoder ( magnets and Reed switches , )
I would put something like a nano in each station to control each feeder and communicate back to a host to set times etc - then if one station fails the others still work . You need power at each station.
The steppers you have chosen are unlikely to be powerful enough , and you would need something to reference their position in case they miss a step .
I like the idea using a simple gear motor.
Forget about encoders . . .
Just simple turn on turn off with MOSFET for control.
Amount of food proportional to on time.
Disc or auger food movement.
Hello,
Instead of a MOSFET based solution, you can use classical relay technology. There are boards that come with 16 relays that can drive the DC-motors as described above. This is a technology that is very easy to debug in case of malfunction.
Do not forget to provide power to the board itself because the Arduino is only able to drive the optocouplers you find on these boards in most cases.
Take into account that these boards work with inverse logic. (open collector technology on the optocoupler side). 4 Arduino's with 4 of these boards would do the job. Best is to provide 1 power supply for each Arduino-board combination and a buck DCX-DC9 converter to power your Arduino. DCX would be the voltage required by your motors.
The only thing I do not know how many times per hour you feed the fish (I therefore assume 2 times a day which would make ther relays last long enough). You might need a fly wheel diode in some cases depending the type of motor and the disturbances of your power grid you experience, but sometimes this is not essential.
I would sort out and get working the mechanical bits before looking at the easy stuff !
Look at what’s commercially available too - for Inspiration and to look at costs.
A simple spring auger may be enough to move the food.
The simple back and forth action of a servo motor should work too.
Lots of discussion and ideas, but I'm with #9!
No matter which way you go, I hope you’re aware of the VERY hostile operating environment this gear will be working in. Splashes, corrosive elements etc.
The casing, sealing and cabling/connectors all need to be well thought out on top of the electro-mechanical aspects.
That also implies heat dissipation and maintenance planning.
Are all the feeders running the same feed plan with the same food ?
For ten or more units, design a common hardware platform, where these issues are addressed, and the critical parts are easily interchangeable.
If it comes up and works as well as I can imagine it - you can definitely sell them later.
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