Need help. Photon + Stepper driver + Stepper Motor match?

Hardware
1

Hello,

I am working on my own version of the very popular “cat feeder” project. Except my device will feed my 60lb labrador. That being said, I will use your usual cereal dispenser but will modify it to hold a lot more food than just a small plastic cilinder. I have come to ask for help with my hardware selection.

I will use my photon to control a stepper to turn the dispenser knob. For the driver I looked into the Big Easy Driver by Sparkfun but I read that while operating at 2A you need to add a heatsink and I don’t want to keep complicating this project so no decision so far.

For the motor I am looking into a NEMA 17 of at least 80+ oz.in like this one:

here the specs:

The reason for the torque requirements is because I read an “Arduino cat feeder” tutorial where the author stated his 70+in.oz sometimes didn’t have enough torque to turn the knob of a medium-size cat food container. so maybe 80+oz.in will be enough for me, maybe not I don’t know.

Bottom line is I still don’t have a driver, would anyone recommend a driver that would work with my photon and this stepper motor? or another stepper motor of around 80 oz.in or more and a driver for it?. It’s my first project so feel free to critique and or advise, anything helps.

thank you

2

If torque is your main concern, then I would consider using a geared stepper that will give you a lot more torque at the expense of speed (which I assume you don’t need). One something like this. This one is rated at a 1.5A, so it should be ok to use with the BigEasy driver without a heat sink. In your use case, the stepper would only be operating for a short time anyway, to turn the dispenser knob, so I think overheating wouldn’t be a big problem.

3

First time I hear about geared stepper motors, sounds like my solution. Good stuff thanks!

4

Nema 17 Stepper Motor:
https://www.oyostepper.com/category-6-b0-Nema-17-Stepper-Motor.html

My stepper motor are from this site. Also sometimes i got it on ebay or amazon.