Led heart beat by changing brightness

Projects Programming
1

Hi all, here a rookie question.

I want to create a hear beat by changing the brightness of a led.
But something goes wrong in my code.

It looks like it's still sends out high or low instead of a pwm value between 0 and 255.

It's a loop of 8 stages:

50% brightness 750 ms
75 % birghtness 25 ms
100 % brightness 25 ms
75 % birghtness 25 ms
50% brightness 67 ms
75 % birghtness 25 ms
100 % brightness 25 ms
75 % birghtness 25 ms

What do I miss and what's the right code?

Thanx.

Cristian

Down below the code:

const int redled = A1;

void setup(){
    pinMode(redled, OUTPUT);
}

void loop(){
    analogWrite(redled, 127); // brightness 50%
    delay(750);
    
    analogWrite(redled, 191); // brightness 75%
    delay(25);
    
    analogWrite(redled, 255); // brightness 100%
    delay(25);
    
    analogWrite(redled, 191); // brightness 75%
    delay(25);
    
    analogWrite(redled, 127); // brightness 50%
    delay(67);
    
    analogWrite(redled, 191); // brightness 75%
    delay(25);
    
    analogWrite(redled, 255); // brightness 100%
    delay(25);
    
    analogWrite(redled, 191); // brightness 75%
    delay(25);
    
}
2

You can only use analogWrite on certain pins.
A1 is not one of the ones used, unless you have an Arduino Zero - (you didn't tell us what Arduino you are using).

For details of which pins you can use see:
https://www.arduino.cc/reference/en/language/functions/analog-io/analogwrite/

3

Hi John,

I'm using an Arduino Uno.
Changed the pin and now it works's thanx.

Cristian

4

Hi Cristian,
Good to hear that you got it working.

5

Now improve it by making it data driven rather than using fixed program steps

const int redled = 3;

struct dataFormat
{
    byte brightness;
    int period;
};

dataFormat ledData[] = {
    { 127, 750 },   //brightness and delay period for each step
    { 191, 25 },
    { 255, 25 },
    { 191, 25 },
    { 127, 67 },
    { 191, 25 },
    { 255, 25 },
    { 191, 25 }
};

const byte STEPCOUNT = sizeof(ledData) / sizeof(ledData[0]);  //calculate number of steps

void setup()
{
    pinMode(redled, OUTPUT);
}

void loop()
{
    for (int step = 0; step < STEPCOUNT; step++)
    {
        analogWrite(redled, ledData[step].brightness);
        delay(ledData[step].period);
    }
}
6

cool, thanx (-:

7

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