docs.google.com IV. Ultrasonic Distance Sensor Introduction: Ultrasonic Sensor. Background: The default example Ping will not quite work because it expects a 3 pin sensor (SEN136B5B) These pins are: .5V, GND, SIG (signal). . The signal pin is used for both sending a signal (digitalWrite) and receiving a signal (pulseln) Our sensor is a 4 pin sensor, separating sending and receiving: Trig - Trigger pulse .Echo Read a the signal back Gnd You will note in the above sensor documentation, that after a 10 us trigger to the module, the system emits an 8 cycle sonic burst. At that point we can use the pulseln function to read the duration of the returned pulse with pulseln Hardware: Using your arduino and breadboard make sure to connect