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Ultrasonic Distance Sensor

The HC-SR04 measures distances using ultrasound and outputs them in centimeters (cm).

Ultrasonic distance HC-SR04

Technical Information​

  • Dimensions: 45mm x 20mm x 17mm
  • Supply voltage of 5V with a current consumption of less than 2mA
  • Up to 50 measurements per second possible

Ultrasonic sensor setup

Programming (Arduino)​

Code​

This code outputs the measured distance in centimeters to the Serial Monitor.

int trig = 1;  // Trig pin of the sensor is connected to pin 1.
int echo = 2;  // Echo pin of the sensor is connected to pin 2.

// Define variables
unsigned int time = 0;
unsigned int distance = 0;

void setup() {
    Serial.begin(9600); // Starts the Serial Monitor
    pinMode(trig, OUTPUT);
    pinMode(echo, INPUT);
}

void loop() {
    digitalWrite(trig, HIGH);
    delayMicroseconds(10);
    digitalWrite(trig, LOW);
    distance = time / 58;
    Serial.println(distance);
}

Programming (Blockly)​

In Blockly, the sensor can be read using the following block:

Select the port to which you have connected the sensor from the dropdown menu. The trigger and echo pins will then be automatically adjusted.