The HC-SR04 ultrasonic ranging module offers a 2cm - 450cm non-contact measurement with a 3mm accuracy. It comes with ultrasonic transmitters, receiver, and control circuit. To start, use an IO trigger for at least 10us high level signal. The module then sends eight 40 kHz signals and checks for a pulse back. If a signal returns, the high output IO duration gives the time from sending to receiving. You can calculate the distance as (high level time x velocity of sound (340M/S)) / 2. It's easy to wire: connect 5V Supply, Trigger Pulse Input, Echo Pulse Output, and GND. With a 5V DC power supply, 2mA quiescent current, 15-degree effectual angle, and 0.3 cm resolution, it's a great choice. It's cheaper than the Shape IR ranging module with similar accuracy and longer range. The package includes one HC-SR04 Ultrasonic Module, along with a user guide and an Arduino demo.
Using the HC - SR04 ultrasonic sensor is easy. First, wire it up. Connect the 5V Supply, Trigger Pulse Input, Echo Pulse Output, and GND as described. To start a measurement, pull the Trig pin to high level for more than 10us. The module will then start sending out signals and look for a return. If there's an object in front, the Echo pin will go high. The longer the high - level duration, the farther the object is. You can use the formula (high level time x 340M/S) / 2 to figure out the distance. When using it, make sure the power supply is stable at 5V DC. Keep the area around the sensor clear of any obstacles that could interfere with the ultrasonic signals. For maintenance, just keep it clean and dry. Avoid exposing it to extreme temperatures or humidity. And that's all you need to know to get the most out of your HC - SR04 sensor.
