The LED will be switched on and off by vibration. The signal will be send to the output if the LED is on. You need pre-resistors for some voltages.
Pre-resistor:
Rf (3,3V) [Red]= 120Ω
[used with ARM CPU-Core based microcontroller like Raspberry-Pi]
Rf (5V) [Red] = 220Ω
[used with Atmel Atmega based microcontroller like Arduino]