AdraXx HC-SR04 Ultrasonic/Sonar Distance Measuring Sensor Module For Arduino

The HC-SR04 ultrasonic sensor uses sonar to measure distance to an object. It offers excellent range accuracy and stable readings in an easy-to-use package. It operation is not affected by sunlight or black material like Sharp rangefinders are (soft materials like cloth can be difficult to detect). Module main technical parameters: 1.Working Voltage : 5V(DC) 2.Static current: Less than 2mA. 3.Output signal: Electric frequency signal;high level 5V;low level 0V. 4.Sensor angle: Not more than 15 degrees. 5.Detection distance: 2cm-450cm. 6.High precision: Up to 0.3cm 7.Input trigger signal: 10us TTL impulse 8.Echo signal : output TTL PWL signal Mode of connection: 1.VCC 2.trig(T) 3.echo(R) 4.GND The basic operation principle is below : use IO port TRIG to trigger ranging. It needs 10 us high level signal at least Module will send eight 40kHz square wave automatically;and will test if there is any signal returned. If there is signal returned;output will be high level signal via IO port ECHO. The duration of the high level signal is the time from transmitter to receiving with the ultrasonic. Testing distance = duration of high level*sound velocity(340m/s) / 2 You can use the above calculation to find the distance between the obstacle and the ultrasonic module.