Skip to main content

Documentation Index

Fetch the complete documentation index at: https://mintlify.com/wokwi/wokwi-docs/llms.txt

Use this file to discover all available pages before exploring further.

HC-SR04 Ultrasonic Distance Sensor

​
Pin names

​
VCC
Power
Voltage supply (5V)
​
TRIG
Digital Input
Pulse to start the measurement
​
ECHO
Digital Output
Measure the high pulse length to get the distance
​
GND
Ground
Ground

​
Attributes

​
distance
string
default:"400"
Initial distance value, in centimeters

​
Operation

To start a new distance measurement set the TRIG pin to high for 10uS or more. Then wait until the ECHO pin goes high, and count the time it stays high (pulse length). The length of the ECHO high pulse is proportional to the distance. Use the following table to convert the ECHO pulse length in microseconds into centimeters / inches:
UnitDistance
CentimetersPulseMicros / 58
InchesPulseMicros / 148

​
Setting the distance

To change the distance while the simulation is running, click on the HC-SR04 drawing in the diagram and use the slider to set the distance value. You can choose any value between 2cm and 400cm.

​
Arduino code example

#define PIN_TRIG 3
#define PIN_ECHO 2

void setup() {
  Serial.begin(115200);
  pinMode(PIN_TRIG, OUTPUT);
  pinMode(PIN_ECHO, INPUT);
}

void loop() {
  // Start a new measurement:
  digitalWrite(PIN_TRIG, HIGH);
  delayMicroseconds(10);
  digitalWrite(PIN_TRIG, LOW);

  // Read the result:
  int duration = pulseIn(PIN_ECHO, HIGH);
  Serial.print("Distance in CM: ");
  Serial.println(duration / 58);
  Serial.print("Distance in inches: ");
  Serial.println(duration / 148);

  delay(1000);
}
Try this example on Wokwi

​
Simulator examples

Build docs developers (and LLMs) love

Get started for freeTalk to us