HC-SR04 Ultrasonic Wave Module Distance Measuring Transducer Sensor / arduino

HC-SR04 Ultrasonic Wave Module Distance Measuring Transducer Sensor

Features:

Working Voltage : 5V(DC) 
Static Current: Less than 2mA.
Output Signal: Electric frequency signal, high level 5V, low level 0V.
Sensor Angle: Not more than 15 degrees.
Detection Distance: 2cm-450cm.
High Precision: Up to 0.3cm
Input Trigger Signal: 10us TTL impulse
Echo Signal : output TTL PWL signal

Mode of connection:
1.VCC
2.trig(T)
3.echo(R)
4.GND

Module Working Principle:
1.Adopt IO trigger through supplying at least 10us sequence of high level signal.
2.The module automatically send eight 40khz square wave and automatically detect whether receive
the returning pulse signal.
3.If there is signals returning, through outputting 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.