Part list

Part Link Qty
PCB - 2
Teensy USB Board, Version 2.0 http://www.pjrc.com 1
MCP23018 I/O expander Digikey: MCP23018-E/SP-ND 1
3.5mm TRRS connector Digikey: CP-43514-ND 2
USB mini B connector Digikey: WM17115-ND 1
USB mini B plug Digikey: H2955-ND 1
0.1 UF ceramic capacitor Digikey: BC2665CT-ND* 1
1N4148 diode
(SOD-123 package (SMD),
or DO-35 (through hole 0.3" pitch))
Digikey: 1N4148FS-ND*
Digikey: 1N4148W-FDICT-ND*
2.2K Ω resistor Digikey: 2.2KQTR-ND* 2
3mm T1 LED Digikey: 160-1034-ND*
~220 Ω resistor (match to led) Digikey: 220QBK-ND* 3
Cherry MX switch Mouser: MX1A-***** 76-80
USB cable Male A to male mini B USBFirewire: www.usbfirewire.com* 1
TRRS cable MyCableMart: www.mycablemart.com* 1
*equivalent components can be used.