Build the electronic parts

Note (2024): Just a RaspberryPi is enough to start. For MIDI, you can use USB MIDI keyboards or a USB MIDI interface. I always recommend to start with only a Raspberry Pi + the software. You can always add the hardware parts later, they are not needed to start, there is no need to build the electronic parts to start. PS: if you want to encourage this open-source project, feel free to buy our commercial products on yellownoiseaudio.com :-)

SCHEMATICS

BILL OF MATERIALS

• Raspberry Pi 2 : ~ 39€
• Sparkfun 7-segment display : ~ 12 €
• USB DAC PCM2704 : ~ 6,50 €
• PCB SD card reader : ~ 1 €
• Sparkfun microUSB breakout : ~ 2 €
• 3.5mm stereo jack socket
• USB A connector (for PCB)
• 2 * Digitast switch
• MIDI socket
• veroboard / perfboard
• female-female Dupont cables
• pin headers
• 3 resistors: 1 x 220Ω, 1 x 10 KΩ, 1 x 1 KΩ, and 1 diode: 1N4148
• 1 optoisolator 6N138