HC-SR04 Ultrasonic Distance Sensor Module

Description 
The ultrasonic sensor HC-SR04 uses sonar to determine the distance to an object. It offers excellent non-contact range detection with high accuracy and stable readings in an easy-to-use package, from 2cm to 400 cm or 1” to 13 feet. Its function is not affected by sunlight or black material like Sharp range finders are (although acoustically soft materials like cloth can be difficult to detect).
The modules include ultrasonic transmitters, receiver and control circuit.

Module Working Principle:
1. Adopt the IO trigger by supplying at least a 10us sequence of high-level signals.
2. The module automatically sends eight 40khz square waves and automatically detect whether to receive the returning pulse signal.
3. If there are signals returning, through outputting a high level and the time of high level continuing is
the time of that from the ultrasonic transmitting to receiving. Test distance = (high-level time * sound velocity (340M/S) / 2.

Features
Input Voltage: 5V
Working Current: 15mA
Working Frequency: 40KHz
Induction Angle: <15°
Distance Range: 2cm ~ 400cm
Resolution : 0.3cm
Trigger Input Pulse Width: 10uS
Pin Number: 4 Pin
Interface: TTL
Size: 45mm x 20mm x 15mm

Note: This module is not suitable to connect with electric power. If you need to do this, the GND terminal of this module should be connected first, otherwise, it will affect the
the function of module.