The Kickbee is a wearable device made of a stretchable band and embedded electronics and sensors. Piezo sensors are attached directly to the band, and transmit small but detectable voltages when triggered by movement underneath. An Arduino Mini microcontroller transmits the signals to an accompanying Java application wirelessly via Bluetooth. (a SparkFun BlueSMIRF v2 module that communicates serially with a Macbook Pro)
The Java application receives the sensor values and analyzes them. When a kick event is detected, a Twitter message is posted via the Twitter API. I chose to use Twitter because it is easy to initiate an SMS message to any mobile phone when a kick is detected. It also acts as a data log that can be accessed programmatically for visualization or archiving.