• 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: Argon ONE V3 Case with FAN IR For Raspberry Pi 5 Raspberry Pi Pico 2 RP2350-Matrix Development Board 8×8 RGB LED Matrix QMI8658 6-Axis Sensor Raspberry Pi 3.5 inch e-Paper link (G) RYBW 384x184 For Arduino / Jetson Nano / STM32 i7-1165G7 1.33TFLOPS RAM-4G eMMC-16 High Performance AI at the Edge X1007 Raspberry Pi 5 PCIe to Dual 2.5" SATA HDD/SSD Double-SATA (NOT BOOT From SATA/SSD Milk-V Duo Ethernet TVBOX Kit Luckfox Pico Ultra And 4inch LCD RGB Captive TouchScreen Display Raspberry Pi 14 inch LCD 2K HDMI /Type C Display Capacitive TouchScreen 2160x1440 For Jetson Nano/mini Computer PC Install Espressif IDF Plugin Tutorial User Guide Raspberry Pi 5 POE PCIe To M.2 E KEY NGFF WIFI7 WIFI6 For BE200/AX210/AX200/RTL8822CE LCD1602 I2C Module PWM Adjustable backlight 3.3V/5V For Arduino/ Raspberry Pi/ Pico/ Jetson Nano/ ESP32 Gyroscope Sensor Raspberry Pi Pico 2 RP2350-One Mini Board Type-A RP2350A Sipeed NanoKVM Cube KVM HDMI Remote OS Control Manager Install /Power Control /Remote Desktop Server UART PC U Industrial RS485 Modbus RTU Relay Raspberry Pi 5 PCIe to 4-CH M.2 NVMe 4-Ports SSD Board HAT Pi5 Four-Times Raspberry Pi ESP32 Thermal imaging