HC-SR04 Ultrasonic Sensor
Power Supply: 5V DC
Quiescent Current: Effectual Angle: ﹤15°
Ranging Distance: 2cm - 500 cm
Resolution: 0.3 cm
Output Signal: Electric frequency signal, high level 5V, low level 0V
Mode of Connection: VCC/ trig(T)/ Echo(R)/ GND (VCC supply 5V, and GND is ground wire. TRIG is trigger control signal input, ECHO is echo signal output.)

Ultrasonic Sensor Module Working Principle
Pull the Trig pin to high level for more than 10us impulse, the module start ranging.

The module automatically sends eight 40KHz square wave to detect whether a signal is returned.

Finished ranging, If you find an object in front, Echo pin will be high level, and based on the different distance, it will take the different duration of high level.

So we can calculated the distance easily. The distance = ((Duration of high level)*(Sonic :340m/s))/2. Distance L = 1/2 x T x C

Package Include:
5 x New Version HC-SR04 Ultrasonic Sensors
3 x Mounting Bracket with Screws
10 x Female-Male Dupont Cables
10 x Female-Female Dupont Cables