Automatic fish feeder

I hope I am in the right place…
I wish to construct an automatic fish feeder. It consists of a hopper over a tube with an auger delivery system. The auger rotates for a certain time and deposits pellets into the water. The amount of food delivered is determined by the number of revolutions of the auger.
The auger is a 3/4 inch wood auger bit inside a pvc pipe. The auger needs to turn slowly - lees than 30 rpm. As I am not sure of how slowly I need to be able to vary the speed. So what I want is some advice as to how to set this up.
I need

  1. an appropriately sized motor
  2. a variable speed controller
  3. a timer with one second increments
    As the auger will be loaded with pellets when at rest, the motor will need sufficient torque to overcome the initial inertia.
    I would greatly appreciate any advice…
    with thanks

Hi Steve, what a great project! I’d suggest that even a tiny motor will do what you need. Your main issue is getting the speed slow enough. The Tamiya 72001 gearbox has multiple stages of reduction that you can add/remove. The more stages you add the slower it goes and with more torque.

You’ll then need to work out a coupling to get the gearbox and auger mated together. Which one you choose will depend on the shaft size of your auger. That covers the mechanics.

On the electrical side you’ll need a programmable controller like this Arduino with an add-on to control the motor, like this one.

We’d love it if you keep us up to date with your project. We’re makers too!