Peg - Haptic Tuner

Peg is a tuner that lives on your wrist and lets you tune through haptic feedback. Play a note and Peg works out which one it is. An upward pulse means too low, a downward pulse means too high. The pulses speed up as you get closer, then go silent once the string has been tuned. Convenient, so you don't have to look at a separate display to tune, but you can instead feel it.