Adafruit NeoTrellis RGB Driver PCB for 4x4 Keypad | The Pi Hut
Adafruit Trellis Monochrome Driver PCB for 4x4 Keypad & 3mm LEDs : ID 1616 : $9.95 : Adafruit Industries, Unique & fun DIY electronics and kits
GitHub - rbnstubbs/trellis-monome: A monome clone using the Adafruit Trellis keypads based on the original arduinome: http://sourceforge.net/projects/arduinome