I bake my own bread, and the tedious part isn't the work — it's the waiting and the looking-up. How long does this dough knead? How long does it rest? When does the oven need to go on?
So a Raspberry Pi Model A does it for me. It drives my grain mill and times the kneading machine, both switched through a simple relay. I pick the recipe I bake most often, press the button, and the Pi walks through the whole sequence of kneads and rests on its own, showing what it's doing on a small OLED.
When it needs me — to switch the oven on, to turn the temperature down — the buzzer plays music. That way I don't have to keep checking on it either.
The finished controller — the machine plugs into the socket on top, the OLED shows where the programme has got to, and the buttons live underneath.
 ▶ Milling Fresh flour going straight from the mill into the mixing bowl. |
 ▶ The controller mid-run Countdown to the next step, with the progress bar filling up. |
Press the button and it works through the sequence on its own:
| Step | Machine | Display says |
|---|---|---|
| Knead | on | "Button pressed! kneading very hard" |
| First break | off | "taking a first break — relax with Max" |
| Quick knead | on | "just a quick first knead" |
| Second break | off | "second break" |
| Quick knead | on | "second quick kneading" |
| Last break | off | "taking the last break" |
| Oven | off | "switch the oven on!" → plays Crazy Frog |
| Final knead | on | "nearly finished, just a second" |
| Baking | off | Popcorn plays when it's time to turn the temperature down |
| Done | off | The Final Countdown |
Before you start, the display works out and shows the finishing time — it takes the programme length, adds it to the clock, and tells you when the bread will be out, so you can decide whether you really want to start baking at half past nine.
The melodies aren't decoration. The Pi can't turn the oven on or change its temperature, so it makes a noise loud enough to fetch someone who can.
- Raspberry Pi Model A
- Relay on GPIO 17, switching the socket that drives the mill and the kneading machine
- SSD1306 OLED (128×64) over SPI — CS on D5, DC on D6, reset on D4
- Push button on GPIO 26
- Red LED on GPIO 23
- DHT11 temperature and humidity sensor
- Buzzer for the melodies
Pi_kneader.py the main programme
finishing_time.py works out when the bread will be done
melody.py buzzer tunes
dht11.py temperature and humidity sensor driver
gpiozero
adafruit-circuitpython-ssd1306
adafruit-blinka
pillow
The display uses a bitmap font at /home/pi/slkscr.ttf — point that at whatever font you have.
This switches mains voltage through a relay to drive a kitchen appliance. If you build something like it, do the mains side properly and don't leave it running unattended.
Also note the step timings in Pi_kneader.py are currently set to 5 seconds each for testing.
The real durations are in the comments next to them (720 s knead, 900 s rest, and so on) —
put those back before you trust it with actual dough.