Detects handshakes and writes to GATT service characteristic on detection. Designed around Adafruit's BlueFruit LE SPI Friend and the ADXL337 accelerometer.

You will need the Arduino library for nRF51822-based BLE modules, which can be found on Adafruit's Github. Download the .zip file and import it into the Arduino desktop app.

Adafruit Bluefruit LE SPI Friend - Bluetooth Low Energy (BLE)
The UART version is also supported, though the appropriate lines must be uncommented.

SparkFun Triple Axis Accelerometer Breakout - ADXL337
Most SparkFun, and many third-party, analog accelerometers should work. The thresholds and maximum raw accelerometer values should be modified according to the board's specifications.

Arduino Uno
I used the Uno since it was the most conveniant choice, but most board should work.