DescriptionThe HC-SR04 Ultrasonic Sensor is widely used for non-contact distance measuring from 2cm – 400cm. The module includes ultrasonic transmitters, receiver and a control circuit.The module works in the following way:1. Send a 10 µs high level pulse to the trigger (TRIG) pin of the module from a microcontroller.2.The module will automatically send eight internally generated 40khz pulses from the transmitter and receive the echo at the receiver.3. A TTL level pulse will be sent from ECHO pin of the module. The width of the pulse is in proportion to the distance measured. Distance = (high level time * sound velocity / 2) . Generally sound velocity = 340 m/sTechnical Parameters:1. Working Voltage: 5 VDC2. Static current: Less than 2mA3. Operating Current: 15mA3. Output signal: Electric frequency signal, high level 5V, low level 0V4. Sensor angle: Not more than 15 degrees5. Detection distance: 2cm-400cm6. Precision: Up to 0.3cm7. Input trigger signal: 10us TTL impulse8. Echo signal: Output TTL PWL signal
