HC-SR04 Ultrasonic Proximity sensor Range Finder

The HC-SR04 ultrasonic sensor uses sonar to determine distance to an object like bats or dolphins do. 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 (although acoustically soft materials like cloth can be difficult to detect).
Ultrasonic Ranging Module HC-SR04 provides 2cm-300cm non-contact distance sensing capabilities,Ranging accuracy up to 3mm; module comprises an ultrasonic transmitter, a receiver and a control circuit.
Basic operating principle:

1. IO port TRIG trigger ranging to at least 10us high level signal;

1. the module automatically sends eight 40khz square wave, automatically detects whether a signal return;

1. a signal to return to a high output through the IO port ECHO high duration of ultrasound wave from the transmitter to the time of the return. Test distance = (high level time * sound velocity (340M / S)) / 2;

Reliable, high performance, high accuracy, blind area within 2cm

Specification:

• Voltage：DC5V
• Current：less 2mA
• TTL：higher 5V
• Sensing angle：Less than 15 degree
• Sensing distance：2cm-450cm
• Accuracy：about 0.3cm
• PCB Dimension：4.5*2.0CM
• Connection:  VCC, trig(Control),   echo(Receive), Out, GND