HC-SR04 Ultrasonic Sensor is an ultrasonic ranging sensor. This economical sensor provides 2cm to 400cm of non-contact measurement functionality with a ranging accuracy that can reach up to 3mm. Each HC-SR04 module includes an ultrasonic transmitter, a receiver and a control circuit. There are only four pins that you need to worry about on the HC-SR04: VCC (Power), Trig (Trigger), Echo (Receive), and GND (Ground). The basic principle of work:
- Using the IO trigger for at least 10us high-level signals.
- The Module automatically sends eight 40 kHz and detects whether there is a pulse signal back.
- IF the signal back, through high level, time of high output IO duration is the time from sending ultrasonic to returning. Test distance = (high level time×velocity of sound (340M/S) / 2
- Operating Current: 15mA
- Measure Angle: 15°
- Ranging Distance: 2cm – 400cm
- Working Frequency: 40Hz
- Trigger Input Signal: 10uS TTL pulse
- Echo Output Signal: Input TTL lever signal and the range in proportion