Egg Roller
The eggs have to be turned every 4 to 6 hours for about a third. I guess there are many different ways to do that, but I decided to reuse my old Lego Technic race car and turned it into an egg moving device. It contains all the parts needed. The rollers are made of 2.5cm PVC tubes and I pressed Lego car wheels into them to connect them to the mechanics. I then simply attached a stepper motor to control the egg movement with the RaspberryPi. The device has space for about 16 eggs.
The stepper motor runs on 1.5A and has a step angle of 1.80°. It is powerful enough to move the eggs without issues and easy to control with the DRV8825 stepper driver (more details in the controller part). I chose a 12V motor to use the same power source as for the heating element. Vref was set to 0.74V; step mode was set to 101 (32 microsteps/step) to increase precision and strength.