Several months ago a friend of mine really into making bread inquired about a possible solution for proving bread dough and making pre-ferment starters in the winter. You see, here in Canada winters are cold. Very cold. And heat isn't free. Yeast likes to be in nice warm moist conditions, but my wallet likes to be in the cold with a thick sweater.
So the goal was to create an efficient device that monitors temperature and switches a heat source on/off as necessary to maintain a constant temperature inside of an enclosed space such as a camping cooler.
And here is the result! It's based on the bare minimum circuitry needed for an Arduino compatible board and then builds on top of that; character LCD display, two buttons, DS18S20 temperature sensor, and a small relay for switching an AC lamp.
Source code, schematic, PCB layout
- source files from my git repo, or github
- see README file for ATmega flashing details
- v1 PCB artwork for toner transfer or exposing pre-sensitized copper clad
- v1 schematic
The doughduino deviates slightly from the Arduino on a breadboard; it does not have a power supply regulator so an external 5v supply is needed. I was pleasantly surprised to find that the guts from an old cell phone charger worked just fine (many chargers are 5 volt, 1 amp supplies).