Ultrasonic Sonar Sensor

Description

The HC-SR04 Ultrasonic Distance Sensor is a popular and affordable sensor module used in robotics and automation systems to detect objects and measure distance using ultrasonic waves.

It works by emitting a high-frequency sound pulse and measuring the time it takes to reflect back. With a wide detection range and easy-to-use 4-pin interface, it integrates perfectly with Arduino, Raspberry Pi, and other microcontroller platforms.

🔍 What This Sensor Is & What It Does

The HC-SR04 Ultrasonic Sensor measures distance using sound waves.
It sends out an ultrasonic pulse and measures how long it takes to bounce back.
Perfect for:

• ✅Obstacle detection

• ✅Robotics & car avoidance

• ✅Smart dustbin

• ✅Water tank level

• ✅Security motion detection

• ✅Autonomous robots

• ✅Parking assist

• ✅Industrial distance sensing

Whether you’re building a line-following robot, obstacle-avoiding car, or smart parking system — this is the go-to sensor. Get it now from Dream RC, Bangladesh’s trusted robotics supplier.

⚙️ Product Features & Specifications

⚡ Power Requirements

📦 Package Includes

• 1 x HC-SR04 Ultrasonic Distance Sensor Module

🔌 Wiring Diagram (Arduino UNO)

HC-SR04 → Arduino UNO

💻 Arduino Sample Code (Beginner-Friendly)

Ultrasonic Sensor / Sonar Sensor Sample / Demo Code For Arduino, ESP 32 & ESP 8266

// Dream RC (dream-rc.com) - Ultrasonic Sensor Code

#define TRIG 13    // TRIG pin (ESP8266: D5, ESP32: 4)
#define ECHO 12    // ECHO pin (ESP8266: D6, ESP32: 5)

void setup() {
  Serial.begin(9600);   // #(ESP recommended: 115200)
  pinMode(TRIG, OUTPUT);
  pinMode(ECHO, INPUT);
}

void loop() {
  digitalWrite(TRIG, LOW);
  delayMicroseconds(2);
  
  digitalWrite(TRIG, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG, LOW);
  
  long duration = pulseIn(ECHO, HIGH);
  float distance = duration * 0.034 / 2;    // Convert Time to CM

  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");

  delay(500);   // Add Delay To The Parogram
}

📌Library Dependencies

No external libraries required.
The HC-SR04 uses only built-in Arduino functions:

• ✅digitalWrite()

• ✅digitalRead()

• ✅pulseIn()

• ✅delayMicroseconds()

📤 Sample Serial Output

Distance: 24 cm
Distance: 25 cm
Distance: 24 cm
Distance: 23 cm

• Values fluctuate ±1 cm — normal

• “0 cm” = no object or weak echo

• Large numbers = too far or wrong wiring

🎯 Accuracy Table

🔧 Troubleshooting Guide

✔ Always getting 0❓

• ❌Object too soft (cloth, sponge)

• ❌Wrong wiring TRIG/ECHO

• ❌Using 3.3V instead of 5V

• ❌Bad USB power

✔ Random unstable readings

• ✅Use short wires (<20cm)

• ✅Add capacitor (10–100 µF) across VCC–GND

• ❌Avoid vibration from motors

✔ ESP32/ESP8266 not working

• ✅Echo must be reduced to 3.3V

• ✅Use 10k + 5k voltage divider

✔ Always shows same value

• ✅TRIG not receiving 10µs pulse

• ✅Code running too fast (add delay)

🧩 Compatibility Table

❓ FAQ (Frequently Asked Questions)

1. What is the range of HC-SR04?

✅2 cm to 400 cm.

2. Can HC-SR04 work outdoors?

✅Yes, but sunlight and wind reduce accuracy.

3. Why does HC-SR04 show unstable values?

⚠️Long wires, vibration, low power, or soft materials.

4. Can I use it with ESP32 or ESP8266?

✅Yes — but Echo pin needs 5V → 3.3V voltage divider.

5. Can ultrasonic sensors detect water?

✅Yes, if the water surface is still (not splashing).

🚚 Dream RC is giving you the best deal in Bangladesh – high quality at the lowest price!

💬 What is the Ultrasonic Sonar Sensor price in BD (Bangladesh) & why buy from us?

The Ultrasonic Sonar Sensor current price in Bangladesh is 89 BDT.
From us – Dream RC, you can get Ultrasonic Sonar Sensor at the most affordable price with the lowest delivery charges & fast shipment all over Bangladesh.