LilyPad: vibe board

Apply 5V and be shaken by this small, but powerful vibration motor. Works great as an physical indicator without notifying anyone but the wearer. This version uses a surface mount motor which is less likely to be damaged during use.

Product page on SparkFun: DEV-11008. Wearable electronics with Arduino LilyPad - a guide: http://web.media.mit.edu/~leah/LilyPad/