ESP8266-Arduino programming example-HC-SR04 ultrasonic sensor driver

HC-SR04 Ultrasonic Sensor Driver

1. Brief introduction to HC-SR04

The HC-SR04 ultrasonic sensor uses sonar to determine the distance to objects such as bats or dolphins.The ultrasonic ranging module HC-SR04 provides 2cm-400cm measurement, and the ranging accuracy can reach 3mm.The module includes an ultrasonic transmitter, receiver and control circuit.

The workflow of the HC-SR04 ultrasonic sensor is as follows:

1. IO trigger of at least 10us high level signal
2. The module automatically sends 8 40 kHz and detects if there is a pulse signal back.
3. If there is a signal return, through high level, the high level output IO duration is the time from sending the ultrasonic pulse to returning.

Test distance = (high level time × speed of sound (340M/s) / 2)

2. Hardware preparation

• ESP8266 NodeMCU development board
• One HC-SR04 sensor module
• Panel one
• Several DuPont lines
• A data cable

The hardware wiring diagram is as follows:

3. Software preparation

• Arduino IDE or VSCode + PlatformIO

In the previous article, I gave a detailed introduction to how to build the ESP8266 development environment, please refer to:

• ESP8266-Ard