Interfacing Arduino ultrasonic sensor with Matlab/pulse timing in Matlab?

I'm trying to make a ball on beam system both simulated in matlab, and built in real life.

So, I'm trying to turn a servo in matlab based on input from an SR04 ultrasonic sensor, but I can't measure the pulse lengths from the SR04 sensor.

clc
clear all
a = arduino('com3', 'uno', 'Libraries', 'Servo')
s = servo(a, 'D4')
pinMode = configurePin(a,'D6')

clear s;
s = servo(a, 'D4', 'MinPulseDuration', 5.44*10^-4, 'MaxPulseDuration', 2.4*10^-3);
xcv = 1/100;

for time = 0:0.05:1

          writeDigitalPin(a, 'D5', 0); 
  tic
          pause(0.000005)
          writeDigitalPin(a, 'D5', 1);
          pause(0.00001)
          writeDigitalPin(a, 'D5', 0);

toc
duration = toc-tic

%duration = pulseIn(D5, HIGH);

          cm = (duration/2) / 29.1
          fprintf('%d\n', cm)
          fprintf('cm');
          pause(50)

end

    for angle = 0:0.05:1
         writePosition(s, angle);
         current_pos = readPosition(s);
         current_pos = current_pos*180;
         fprintf('Current motor position is %d degrees\n', current_pos);
         pause(0.5);
    end

My code has no problem running the servo to some random angles, but pulseIn() isn't an available function in the Arduino Matlab library as far as I could find it.

Here's my working arduino code for the Arduino IDE that outputs the distance as an integer WITHOUT using the NewPing library.

int trigPin = 5;    //Trig - green Jumper
int echoPin = 6;    //Echo - yellow Jumper
long duration, cm, inches;

void setup() {
  //Serial Port begin
  Serial.begin (9600);
  //Define inputs and outputs
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
}

void loop()
{

    // The sensor is triggered by a HIGH pulse of 10 or more microseconds.
    // Give a short LOW pulse beforehand to ensure a clean HIGH pulse:
    digitalWrite(trigPin, LOW);
    delayMicroseconds(5);
    digitalWrite(trigPin, HIGH);
    delayMicroseconds(10);
    digitalWrite(trigPin, LOW);

    // Read the signal from the sensor: a HIGH pulse whose
    // duration is the time (in microseconds) from the sending
    // of the ping to the reception of its echo off of an object.
    pinMode(echoPin, INPUT);
    duration = pulseIn(echoPin, HIGH);

    // convert the time into a distance
    cm = (duration/2) / 29.1;

    Serial.print(cm);
    Serial.print("cm");
    Serial.println();

    delay(30);
  }

Feel free to change whatever you need to change, and if you know how to make the whole function loop back so it is constantly receiving info from the sensor and causing a change in the servo angle that would be a huge help as well.

[Robert Lyle]

Alright I figured it out there's an Arduino library and a separate HC-SR04 library, which has included examples for using the HR04 ultrasonic sensor.

[Hamza Abbasi]

can you please tell me what should i do if i am using three ultrasonic sensors and i want to plot response of trigger and echo pulse of each sensor individually

Answer 1

[Purawin Subramaniam]

Did you solve your problem?

[Madhu Govindarajan]

I think Robert mentions that he is using this - https://www.mathworks.com/matlabcentral/fileexchange/57898-hc-sr04-add-on-library-for-arduino

HTH, Madhu