Connectivity and control
I suspected an Arduino would be the ideal platform to control my motor, as I already had some experience with the hardware. The initial purchase list was based on the following, which I hoped would let me access NTP servers to schedule the servings, drive the motor, and post the result to the web.
Proposed parts list:
I soon realised that with almost half of my £60 budget already gone on real world interfaces, I would have to find a cheaper way to control it all if I was going to keep to budget. I considered simply using a standard household timer socket to switch on the Arduino twice a day, and have a simple sketch drive the motor for 2 seconds, then stop. The saving didn’t really justify losing the ability to send and receive feed activity from the web, and I looked for a cheaper way to secure the WiFi feature.
As with ‘gear motor’ the key phrase here was 8266. Now knowing what I was searching for, I found myriad affordable 8266 modules which seemed to promise what I wanted. Unfortunately they also seemed to throw up many dependencies, such as 3.3V power requirements, FTDI cables, python libraries, arcane IDEs, and I began to think I would most likely end up bricking whatever I ordered.
Fortunately, my google fu eventually located the Adafruit Feather HUZZAH with ESP8266 WiFi (https://shop.pimoroni.com/products/adafruit-feather-huzzah-with-esp8266-wifi), which seemed to be the equivalent of a small form factor Arduino, with the ESP8266 functionality built in. Costing about the same as the plain Arduino board, programmable using the Arduino IDE and using a standard USB A / USB micro B cable (to fit most eReaders, smartphones, cameras, etc) for power and data this was an easy win.
With the change in form factor and voltage (the Feather runs 3.3V logic rather than the Uno’s 5) the motor shield was also out, so I looked for components that might do this on the breadboard. I soon came across MOSFETs, which proved to be far more affordable and flexible solution. My parts list now looked like this:
This left me with about £20 for any remaining parts, which I quickly used up by buying a proper CNC shaft connector, a 37mm DC geared motor mounting bracket, a dual power supply capable of servicing the 12V motor and the feather (which will happily run on 5V from the USB connector) and a bag of bits to help me connect up the MOSFET.