MATLAB Examples

# Control HC-SR04 Ultrasonic Sensor

This example shows how to use the MATLAB® Support Package for Arduino® Hardware to control a HC-SR04 ultrasonic ranging module capable of measuring distances in the 2cm to 400cm range.

## Hardware Requirements

• Arduino board
• HC-SR04 ultrasonic sensor

## Hardware Setup

• Connect Trig pin to pin D12 on Arduino board.
• Connect Echo pin to pin D13 on Arduino board.
• Connect VCC pin to 5V pin on Arduino board.
• Connect GND pin to GND pin on Arduino board. ## Create HCSR04 Object

Create arduino object with JRodrigoTech/HCSR04 add-on.

```a = arduino('COM38', 'Uno', 'Libraries', 'JRodrigoTech/HCSR04') ```
```a = arduino with properties: Port: 'COM38' Board: 'Uno' AvailablePins: {'D2-D13', 'A0-A5'} Libraries: {'JRodrigoTech/HCSR04'} ```

Create ultrasonic sensor object with trigger pin D12 and echo pin D13.

```sensor = addon(a, 'JRodrigoTech/HCSR04', 'D12', 'D13') ```
```sensor = HCSR04 with properties: Pins: 'D12'(Trigger), 'D13'(Echo) ```

## Measure Sensed Distance in Meter

```val = readDistance(sensor); sprintf('Current distance is %.4f meters\n', val) ```
```ans = Current distance is 0.0800 meters ```

## Measure Distance from Sensed Time

The distance can be computed from the sensed time using this equation, distance = (time x speedOfSound) / 2. Assume speed of sound is 340m/s here.

```t = readTravelTime(sensor); sprintf('Current distance is %.4f meters\n', 340*t/2) ```
```ans = Current distance is 0.0918 meters ```

## Clean Up

```clear sensor clear a ```