So as well as technology, I love baking – to the extent that I bake stuff to sell with all the shenanigans that goes with that. Local authority inspections, food hygiene certificates, insurance, blah….
So that’s an A+ model in a nice Pimoroni case with an Adafruit perma proto-plate on-top with some “stuff” to control the oven stuck on the side of the oven with some Blu-Tack for now. It’s powered up – stays online all the time now (I had issues with an old Wi-Fi dongle, replaced it with one of the Foundation approved ones and it’s been rock-solid since then). The three thin cables go to thermocouples inside the oven compartment and the grey cable goes to a SSR (Solid State Relay) inside the top of the oven. The Green LED is actually a bi-colour LED wired across 2 GPIO pins with a resistor. It can be off, green, red or if I could be bothered to write code to alternate the pins, a sort of muddy yellow. I just use it to indicate the heater being on (red) or off (green).
So how do you control an oven? Lets break it down into steps. One thing I was interested in was just how rubbish my oven really was. I already knew where the hot spots were (the bottom of the oven is hotter than the top – who’d have thought that?) and how unevenly it cooked as well as just how approximate the temperature dial was (plus or minus a fruit cake) so the first task was to measure the temperatures. Most of the temperature sensors you see people plugging into the Pi are only good to about 120°C or thereabouts. I wanted something that was good to 300°C or more. (This oven maxes out at 250, but I have others that go to 300…)
Each Friday is PiDay here at Adafruit! Be sure to check out our posts, tutorials and new Raspberry Pi related products. Adafruit has the largest and best selection of Raspberry Pi accessories and all the code & tutorials to get you up and running in no time!