How to modulate a Light emitting diode (LED) with four different frequencies: 1k, 1.25k, 1.75k and 2k? I want to modulate the LED to use it in indoor positioning process.

How to modulate four Light emitting diodes (LEDs) with four different frequencies: 1k, 1.25k, 1.75k and 2k? I want to modulate the LEDs to use it in indoor positioning process.

LED1>>>>1K Hz

LED2>>>>1.25K Hz

LED3>>>>1.75k Hz

LED4>>>>2K Hz

Answer 1

[Abhijeet]

Please use the following steps to modulate the four LEDs with different frequencies using MATLAB:

Define the frequency values for each LED as variables:

    f1 = 1000;   % frequency of LED 1
    f2 = 1250;   % frequency of LED 2
    f3 = 1750;   % frequency of LED 3
    f4 = 2000;   % frequency of LED 4

Define the sampling rate and the duration of the modulation signal:

    Fs = 8000;   % sampling rate
    t = 0:1/Fs:1;  % duration of modulation signal (1 second)

Create the modulation signals for each LED using the sine function and create a matrix to hold these signals:

    mod1 = sin(2*pi*f1*t);
    mod2 = sin(2*pi*f2*t);
    mod3 = sin(2*pi*f3*t);
    mod4 = sin(2*pi*f4*t);
    modulation = [mod1; mod2; mod3; mod4];

Initialize the LEDs using the Arduino interface in MATLAB:

    a = arduino();
    led1 = 'D3';   % digital pin connected to LED 1
    led2 = 'D5';   % digital pin connected to LED 2
    led3 = 'D6';   % digital pin connected to LED 3
    led4 = 'D9';   % digital pin connected to LED 4
    configurePin(a, led1, 'DigitalOutput');
    configurePin(a, led2, 'DigitalOutput');
    configurePin(a, led3, 'DigitalOutput');
    configurePin(a, led4, 'DigitalOutput');

Loop through the modulation signals for each LED and turn the corresponding LED on and off based on the signal value:

    for i = 1:length(t)
    if modulation(1,i) > 0
        writeDigitalPin(a, led1, 1);
    else
        writeDigitalPin(a, led1, 0);
    end
    
    if modulation(2,i) > 0
        writeDigitalPin(a, led2, 1);
    else
        writeDigitalPin(a, led2, 0);
    end
    
    if modulation(3,i) > 0
        writeDigitalPin(a, led3, 1);
    else
        writeDigitalPin(a, led3, 0);
    end
    
    if modulation(4,i) > 0
        writeDigitalPin(a, led4, 1);
    else
        writeDigitalPin(a, led4, 0);
    end
    
    pause(1/Fs);
end

This code will continuously loop through the modulation signals for one second, turning each LED on and off based on the corresponding signal value.

[Aly Khafagy]

Thank you so much, I have another question, i cannot find the LED bulb lamp on simulink, do you have any idea where can i find a LED lamp on simulink??