Ultrasonic Range Finder Module (HC-SR04)

The Ultrasonic module detects the distance of the closest object in front of the sensor (from 2 cm up to 400cm). It works by sending out a burst of ultrasound and listening for the echo when it bounces off of an object.

The module sends a short pulse through (Pin 'Trig') to trigger the detection, then listens for a pulse on the Pin 'Echo'. The duration of this second pulse is equal to the time taken by the ultrasound to travel to the object and back to the sensor. Using the speed of sound, this time can be converted to distance.

HC-SR04 Ultrasonic Module
User Manual : um_hc_sr04.pdf
Sales Price : RM10.90


  • Operating voltage : +5V
  • Static current : < 2mA
  • Detection angle : < 15°
  • Range : 2cm ~ 400cm
  • Precision : 0.3cm

Pin Definition:

  • PIN #1 : VCC
  • PIN #2 : Trig
  • PIN #3 : Echo
  • PIN #4 : Gnd