HC-SR04 Ultrasonic Sensor Module

HC-SR04 Ultrasonic Sensor Module

The HC-SR04  Ultrasonic Sensor operates by emitting Ultrasonic waves to gauge the distance to an object, similar to how bats navigate. This makes it a useful tool for distance measurement. The sensor is equipped with two Ultrasonic Transducers. One serves as a Transmitter, emitting a high-frequency Ultrasonic signal, while the other acts as a receiver, waiting for the echo signal that bounces back from any object in its trajectory.

The time interval between the two signals, divided by the speed of sound, provides the distance to the object. The sensor is theoretically capable of measuring distances from 2cm to 400cm, but in practice, it can easily measure up to 75-80cm. These sensors are cost-effective, user-friendly, and energy-efficient. They can be utilized to measure water depth, as waves can travel through water, detect and avoid obstacles in a robot’s path, and serve as a parking assist sensor.

Specifications:

• Operating voltage: +5V
• Operating Current: <15mA
• Theoretical Distance that can be measured: 2cm to 4m
• Practical Distance that can be measured: 2cm to 80cm
• Accuracy: 3mm
• Measuring angle covered: <15°

This module operates on a 5V supply. To initiate the measurement, the trigger pin must be set high for 10 microseconds and then switched off. This prompts the transmitter to emit an Ultrasonic wave at a frequency of 40HZ. The Echo pin stays high for a duration equivalent to the time it takes for the Ultrasonic wave to return to the sensor.

HC-SR04 Ultrasonic Sensor Pinout: The duration for which the Echo pin remains high is measured by the controller, and the distance covered by the wave is calculated by multiplying it with the speed of sound. Therefore, the distance of the object from the sensor is determined by halving the distance covered by the wave.