Keep PWM signal in loop with other things

Projects General Guidance
1

Hi, i'm working on a project with my car and currently i'm faceing a little problem:
In the loop i have multiple things, for example, scan for a RFID card, check a vibration sensor and i also want to keep an PWM signal without any interuptions depending on a button:

void loop()
{
  delay(100);
  // BEGIN OTHERS
  if (analogRead(usaPin) == HIGH) {
    analogWrite(usaoutPin, 120); //about 50% PWM
  }
  else
  {
    analogWrite(usaoutPin, 0);
  }

where usaPin will be a toggler with a resistence and usaoutPin will be the output

i'm also thinking of set this analogWrite from the setup and using the toggler to connect it to my lights (using a capacitor)

What do you think, excepting my possible solution ?

2

PWM will continue to "run" until it's stopped so there's no reason to re-start it every time through the loop.

You might want to set-up an AND condition with a flag that keeps track of if the PWM is running or not. That way you can start PWM only when your usaPin is high and PWM isn't already running.

3

There is a very small chance that analogRead() returns HIGH. analogRead() returns a value between 0 and 1023 (both included). HIGH is defined as 1; so only if analogRead() returns 1, you will set the PWM output to 120.

I do not understand what you try to achieve with a capacitor? I also do not quite understand 'toggler with resistance'.

Maybe you can draw a little schematic for both scenarios (photo/scan of hand-drawn one will do).

4

Tnx for your respond, do you mean like this:

int usaStatus = 0;
int ledStatus = 0;

void loop()
{
  delay(100);
  // BEGIN usalights
  if (analogRead(usaPin) == HIGH) {
    if (usaStatus = 0) {
      analogWrite(usaoutPin, map(usalight, 0, 100, 0, 255)); //set PWM of usa lights
    }
    else
    {
      analogWrite(usaoutPin, 0);
    }
  }
  else
  {
    usaStatus = 0;
  }

and by toggler with resistence i mean a pull up res to track the toggler (that will be on an analog pin because i have no more space for them)

5

Analog pins can be used as digital pins; just use digitalRead().

And I do not understand the rest of the code; you use a variable usaStatus whose value never changes. If you want to detect a statechange, have a look at the statechange dectection example that comes with the IDE.

And why the single '=' in * if (usaStatus = 0) {* ?

6

See the StateChangeDetection example, how to react on button state changes only. Whenever the button state changes, start or stop the PWM output.

7

I currently builded this:

and now looking into State Change detection

int usaStatus = 0;

void loop()
{
  delay(100);
  if (digitalRead(usaPin) == HIGH) { //if toggler is ON
    if (usaStatus == 0) {
      analogWrite(usaoutPin, map(usalight, 0, 100, 0, 255)); //set PWM of usa lights
      usaStatus = 1;
    }
  }
  else //if toggler is off
  {
    if (usaStatus == 1) {
      analogWrite(usaoutPin, 0); //set off usa lights
      usaStatus = 0;
    }
  }
8

You got it :slight_smile:

Eventually replace the delay() by non-blocking debounce code.