Raspberry Pi + HC-SR04 Ultrasonic Distance Sensor: Wiring, Code and Accuracy Tips
Exploring how the HC-SR04 ultrasonic sensor measures distance using sound, and how to wire and program it on a Raspberry Pi.
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 on accuracy limits, environmental effects, and how ultrasonic interference can impact your readings.