Ultrasonic Sensor: What you should know.

What is Ultrasonic Sensor?

The sensor which uses the ultra high frequency sound for doing it's activity is called ultrasonic sensor. 

Ultrasonic sensor HC-SR04: 

• The sensor module consists of ultrasonic transmitter, receiver and the control circuit. 
• It has four pins named Trigger, Echo, Vcc & Ground. 

The working principle of this ultrasonic sensor module is as follows:

1. High level signal is sent for 10us using Trigger.
2. The module sends eight 40 KHz signals automatically, and then detects whether pulse is received or not.
3. If the signal is received, then it is through high level. The time of high duration is the time gap between sending and receiving the signal.
4. Hence, Distance= (time x speed of sound)/2.

Wiring connections: 

1.  Vcc- 5V supply
2. Trigger - Pulse input
3. Echo - Pulse output
4. Ground- 0V

Fig: Typical wiring

Applications:

1. It  can be used to measure distance in range of 2cm-400cm with accuracy of 3mm.
2. Liquid level measurement.
3. Object detection.