Generic · HC-SR04
HC-SR04 Ultrasonic Distance Sensor
KSh 250In stock
Specification
- Part number
- HC-SR04
- Manufacturer
- Generic
- Stock code
- SEN-HCSR04
- Category
- Sensors
- Supply voltage
- 5 V
- Output type
- Digital pulse
- Mounting
- Through-hole
- Availability
- 22 in stock
Details
The standard four-pin ultrasonic ranger. You pulse TRIG, time how long ECHO stays high, and convert to distance. Cheap, reliable enough for obstacle avoidance and tank level, and the first sensor most robots get.
Worth knowing: it does not see soft or angled surfaces well — cloth absorbs the pulse and a surface tilted away reflects it elsewhere. ECHO idles at 5 V, so on a 3.3 V board (ESP32, Pico) put a divider on that pin.
Ask about this part
Answers come from this listing and the assistant can still be wrong — the manufacturer's datasheet is what governs. For anything you are going to wire up, check it there or ask us.
Helpful links
Using this part
Starting points, not finished firmware. Check them against the datasheet.
Measure distance in centimetres
// VCC -> 5V, GND -> GND, TRIG -> D9, ECHO -> D10
// On a 3.3V board, divide ECHO down first.
const uint8_t TRIG = 9, ECHO = 10;
void setup() {
Serial.begin(9600);
pinMode(TRIG, OUTPUT);
pinMode(ECHO, INPUT);
}
void loop() {
digitalWrite(TRIG, LOW); delayMicroseconds(2);
digitalWrite(TRIG, HIGH); delayMicroseconds(10);
digitalWrite(TRIG, LOW);
// Time out after ~30 ms so a missing echo does not block the loop.
unsigned long us = pulseIn(ECHO, HIGH, 30000UL);
if (us == 0) {
Serial.println("no echo");
} else {
// Sound travels ~0.0343 cm/us; halve it for the round trip.
Serial.print(us * 0.0343 / 2.0);
Serial.println(" cm");
}
delay(100);
}