24 Touch MIDI Controller (Atmega32u4)

The controller has 24 capacitive inputs supported by two MPR121 chips. The MCU is Arduin Pro Micro with Atmega32u4 supporting MIDI communication via USB.

Parts:

• 1x Arduino Pro Micro (atmega32u4)

• 2x MPR121 breakout

• 2x LED Ws2812B

• 2x button

• 1x AMS1117 + 2x 100nf capacitor (3.3 stabilizer voltage)

MPR121

Mpr121 run only on +3.3 voltage, you must use voltage regulator for example AMS1117.

• change default adress (0x5A) - cut jumper ADD/GND , and connct ADD to 3v3 (0x5B), ADD to SDA (0x5C), ADD to SCL (0x5D)

• you can connect 4 MPR121 at once i2C

Connections:

• MPR121 → I2c - sda pin - 2 / scl pin - 3 (+ sda and scl 4,7k to 3.3vcc) without logic conver

• Down button → Pin 5

• Up button → Pin 4

• Led ws2812b → Pin 6

Libary:

Code usage Adafruit MPR1121, Adafruit NeoPixel, MIDIUSB and avdweb_Switch

Function:

Mpr121 send MIDI value start from C1 - 36 note midi

• Single click DownButton - change octave -1

• Single click UpButton - change octave -1

• long press DownButton - mute all channels

• long press UpButton - resetting mpr threshold + unmute all channels

Status:

• first led - generate rgb fade effect

• second led - show status connector touched, mute/unmute mode, current change octave

To do in the future:

-more button & rotary encoder // control change ( play, rec, pause, stop, overdub)