An artistic capacitive MIDI USB controller
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| References | Qty | Description | Manufacturer | MPN | Manufacturer | MPN | Manufacturer | MPN | Digikey | Mouser | RS | Farnell |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| C1, C2 | 2 | C 22pF 0805 | KEMET | C0805C220J5GACTU | AVX | 08051A220J4T2A | 399-1113-1-ND | 80C0805C220J5G | 2644258P | 1625484 | ||
| C3, C5 | 2 | C 0.1uF 0805 | Yageo | CC0805KRX7R9BB104 | Murata | GRM21BR71H104KA01L | 311-1140-6-ND | 603CC805KRX7R9BB104 | 6698842 | 3019949 | ||
| C4 | 1 | C 1uF 0805 | TDK | C2012X7S2A105K125AB | Yageo | CC0805KKX7R8BB105 | 311-1456-6-ND | 603CC805KKX7R8BB105 | 7883054P | 1458903 | ||
| D1, D2 | 2 | LED 0805 red | Broadcom | HSMS-C170 | VCC | 7012X1 | 516-1429-6-ND | 630HSMSC170 | 1371306 | 5790839 | ||
| J23 | 1 | USB B Micro Type connector Micro-B Molex 47346-0001 | Molex | 47346-0001 | 47346-0001 | WM17141CT-ND | 538473460001 | 7025475 | 1568026 | |||
| R1, R5 | 2 | R 10K 0805 | Vishay | CRCW080510K0FKEA | Panasonic | ERJ-6ENF1002V | Yageo | RC0805FR-0710KL | 311-10.0KCRDKR-ND | 603RC0805FR0710KL | 6790816 | 2148862 |
| R2, R3 | 2 | R 22 0805 | Panasonic | ERJ-6GEYJ220V | Yageo | RC0805JR-0722RL | 311-22ARCT-ND | 603RC0805JR0722RL | 7326602 | 1799493 |
🎵🍄 TuneShroom
An artistic capacitive MIDI USB controller - Just a small project to practice artistic PCB design and embedded programming. Find out more on my website
Hardware
The PCB was designed in KiCAD using the wonderful svg2shenzhen plugin for Inkscape. The circuit is essentially a Sparkfun Pro Micro, thanks Sparkfun for sharing the schematic! It uses an Atmega32u4 with native USB. Each of the IO pins is hooked directly to one of the touch pads on the front and acts as MIDI key.
Firmware
I started out using Arduino but to access more pins and have more control I decided to go the bare metal approach. The current firmware is a patched version of LUFA which does all the USB stuff for me.
Programming
To compile the firmware go into the project folder and make all.
To Flash it onto the board you need an AVR programmer of some kind and to build a little ISP programmer with some pogo pins.
Some fuses have to be changed from their default using:
avrdude -c usbasp -p ATmega32u4 -U hfuse:w:0xD8:m -U lfuse:w:0xFF:m -U efuse:w:0xCB:
Then it's just a case of programming it with:
avrdude -c usbasp -p ATmega32u4 -U flash:w:TuneShroom.hex