Rotary encoder

A rotary encoder is a knob that sends a digital signal to our microcontroller if you turn it one way, and another signal if we turn it the other way. Perfect for our volume knob! You can press it as well, we'll use this to mute our microphone during meetings.

In this section we'll wire up the rotary encoder and program it.

Wiring

To wire the rotary encoder follow this diagram (my apologies for the non-existing paint skills 😅)

We'll connect the rotary encoder using the shorter (10cm) wires with 2 female plugs on the end.

• GND to GND pin
• 5V to the 3V3 pin on the board (❗❗ NOT THE 5V PIN ❗❗)
• S1 to PIN 9
• S2 to PIN 10
• KEY to PIN 7

Firmware

We'll use the built-in rotary-encoder library to read out our encoder. Follow this tutorial to get the rotary encoder running.

Completed code

import rotaryio
import board
import digitalio
import usb_hid
from adafruit_hid.consumer_control import ConsumerControl
from adafruit_hid.consumer_control_code import ConsumerControlCode

button = digitalio.DigitalInOut(board.D12)
button.direction = digitalio.Direction.INPUT
button.pull = digitalio.Pull.UP

encoder = rotaryio.IncrementalEncoder(board.D10, board.D9)

cc = ConsumerControl(usb_hid.devices)

button_state = None
last_position = encoder.position

while True:
    current_position = encoder.position
    position_change = current_position - last_position
    if position_change > 0:
        for _ in range(position_change):
            cc.send(ConsumerControlCode.VOLUME_INCREMENT)
        print(current_position)
    elif position_change < 0:
        for _ in range(-position_change):
            cc.send(ConsumerControlCode.VOLUME_DECREMENT)
        print(current_position)
    last_position = current_position
    if not button.value and button_state is None:
        button_state = "pressed"
    if button.value and button_state == "pressed":
        print("Button pressed.")
        cc.send(ConsumerControlCode.PLAY_PAUSE)
        button_state = None

Next up installing and programming our keyboard switches.