The Arduino Sensor Kit comes as a standalone kit for only €23.00 or $23.00, or can be purchased with the Arduino UNO Rev3 board as a great value bundle for €38.70 or $38.70.

GND of the module is the common (0V) connection. The digital signal output to be detected (usually marked as DO in the module) is applied to D2 input of the Arduino. Analog output (marked as AO) from ...