Beginner4/7/2026- Author: IoTSpark Maker
ESP32 + HC-SR04: Measuring Distance via Ultrasound (Quick Test Sample Code)
The HC-SR04 measures distance by emitting a 40kHz ultrasonic pulse and timing how long the reflected wave takes to return (time-of-flight).
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4 steps4 components
The HC-SR04 measures distance by emitting a 40kHz ultrasonic pulse and timing how long the reflected wave takes to return (time-of-flight). It's the cheapest and most popular distance sensor — used in obstacle-avoiding robots, water-level measurement, parking alerts, and counting people through a doorway.