To control interface is consisting of four main parts:
- Rotary encoder with push button
- Opto-isolated relay
- 128x32 oled display
- Arduino Nano
The encoder is used to select the different presets. As of now, there are two presets for aeropress and 7 for drip coffee. A curcuit from a mobile charger is providing supply voltage to the arduino from mains.
I had some problems with noice on the encoder signal. I used two 0.1uf caps and 10k resistors to do a hardware debounce, which worked great.Calibrating rate of ground coffee
I needed to figure out the rate of coffee ground pr second. To do this i simply grind for a specified time interval and measure the mass of ground coffee. Calculating backwards i get a rate of:
Now it is easy to convert the amount of coffee from grams to seconds of grinding.
- Shrink in size, so it will fit inside the enclosure
- 3D print and enclosure for the display that fits neatly on the outside of the grinder
- Make a fancy splash screen :)