• sales

    +86-0755-88291180

HC-SR04 User Guide

Arduino connects ultrasonic sensor for distance measurement 

Ultrasonic sensors are suitable for static distance measurement of large flat surfaces. The range of ordinary ultrasonic sensors is about 2cm-450cm, and the resolution is 3mm (the test environment is not so good, and the personal measurement is relatively stable. The distance is about 10cm-2m. If this distance is exceeded, accidental inaccuracies often occur. Of course not Eliminate technical issues.)


The test object is the SRF-04 ultrasonic sensor, which has four pins: 5v power supply pin (Vcc), trigger control terminal (Trig), receiving terminal (Echo), and ground terminal (GND) 



How to use the module: 
Using this module, occupies two IO ports of the single-chip microcomputer, and one IO port is used as the trigger terminal. One IO port is used as the echo PWM signal capture pin. When writing the program, firstly set the level of 8 40K cycles at the TXD pin, and the program is processed into a PWM signal and output from the RXD pin. Once an echo signal is detected, the echo signal is output for our convenience. When we use it, we only need to read the low level time (T). The echo signal is a distance object proportional to the pulse width. The distance can be calculated from the time interval between the transmitted signal and the received echo signal. Formula: uS/58=cm or uS/148=inch. The formula L=340T/2 can also be propagated in the air by sound waves. You can find L (measured distance). If no reverberation signal is detected, the module’s reverberation signal pin will output a level of about 140uS to prevent the transmitted signal from affecting the reverberation signal. 


The working principle of the module: 

IO trigger ranging to at least 10us high signal;

module automatically sends eight 40kHz square wave, automatically detect whether a signal return;

a signal to return to a high IO output, high duration of the ultrasonic time from launch to return.

Test distance = (time high * speed of sound (340M / S)) / 2;


Circuit connection method: 



Arduino program example: 

const int TrigPin = 2
const int EchoPin = 3
float cm; 
void setup() 

Serial.begin(9600); 
pinMode(TrigPin, OUTPUT); 
pinMode(EchoPin, INPUT); 

void loop() 

digitalWrite(TrigPin, LOW); //Send a short time pulse to TrigPin  
delayMicroseconds(2); 
digitalWrite(TrigPin, HIGH); 
delayMicroseconds(10); 
digitalWrite(TrigPin, LOW); 

cm = pulseIn(EchoPin, HIGH) / 58.0//Convert the echo time to cm  
cm = (int(cm * 100.0)) / 100.0//Keep two decimal places  
Serial.print(cm); 
Serial.print("cm"); 
Serial.println(); 
delay(1000); 



TAG: ESP32-C5 WIFI6 Development Board ESP32-C5-WROOM-1 N16R4/N16R8 Raspberry Pi 5 PCIe To M.2 E KEY NGFF WIFI7 WIFI6 For BE200/AX210/AX200/RTL8822CE USB CAN Analyzer Milk-V Raspberry Pi 4 Sound Card OLED-LCD-HAT-A user guide Industrial USB TO RS232/485 (C) UART FT232RNL 2m For 3.3V / 5V For Switchable RS232/RS485 Raspberry Pi MLX90641 Jetson Nano Case Metal Case FT232RNL USB TO TTL Industrial UART (C) User Guide Industrial Isolated Converter 4 inch e Paper HAT+ E Ink Spectra E6 Full-Color 600x400 Screen Display For Arduino /Raspberry Pi /Jetson Nano /STM32 Raspberry Pi Pico 2 RP2350 4inch LCD CAN RS485 QMI8658 Development Board 480x480 TouchScreen Display LVGL HMI I2C Sensor ESP32-P4 Core Board 32MB PSRAM 16MB Flash TOF Time of Flight Laser Range Sensor Mini Radar module UART Serial / I2C Port For Arduino / Raspberry Pi / ESP32 Raspberry Pi 3 LCD HAT Raspberry Pi Pico 2 RP2350 1.43 inch AMOLED TouchScreen Development Board 466x466 1.43inch Display QMI8658 6-Axis | PCF85063 RTC | SD | Battery Port X1300 X1300-A2 Raspberry Pi 5 HDMI to CSI-2 Shield 1080P@60fps & Audio & Video Also AURORA AI Laser Radar And Dual Eye Camera IMU Integrated Positioning Map For Android/ROS+RoboStudio