Raspberry Pi + HC-SR04 Ultrasonic Distance Sensor: Wiring, Code and Accuracy Tips

The HC-SR04 is a popular and inexpensive ultrasonic distance sensor that measures range using sound waves. In this post, we connect it to a Raspberry Pi, explain the electronics behind the Trig and Echo pins, build a safe voltage divider for 3.3 V logic, and write a simple Python script to read accurate distance measurements. Oscilloscope measured signals put theory to the test. We’ll also touch…