Start and stop a blink led with two pushbuttons

[pablocx]

HI folks, I'm new to adruino, not to C, but yes to arduino.
I have 2 push buttons, one LED.
First I used a simple program to swith the on with the push of Button A, and turn it off with the push of button B.
That worked fine.
Then I wanted the LED to turn on and keep blinking, until I pushed button B. I couldn't.
Then, for the LED to start blinking without delay() I used this, but I couldn't find any way to stop it with the push of button B.

int ledPin = 5;
int buttonApin = 9;
int buttonBpin = 8;
unsigned long previousMillis = 0; 
const long interval = 1000; 
int ledState;

byte leds = 0;

void setup() 
{
  pinMode(ledPin, OUTPUT);
  pinMode(buttonApin, INPUT_PULLUP);  
  pinMode(buttonBpin, INPUT_PULLUP);  
}

void loop() 
{
if (digitalRead(buttonApin) == LOW){

   while(digitalRead(buttonBpin) =! LOW){
      
    unsigned long currentMillis = millis();

    if (currentMillis - previousMillis >= interval) {
    // save the last time you blinked the LED
    previousMillis = currentMillis;

    // if the LED is off turn it on and vice-versa:
    if (ledState == LOW) {
      ledState = HIGH;
    } else {
      ledState = LOW;
    }

    // set the LED with the ledState of the variable:
    digitalWrite(ledPin, ledState);
    }   
}
}
}

I used the mills() function to avoid delay(), but the while loop doesn' seem to stop when I press the button B.
This is the circuit attached.
Thank you all in advance.-

Pablo.

[marco_c]

The simplest way to do this is to treat the two things you are doing as separate controls.

1. When the ON button is pressed you set an internal variable to 'true'. When the OFF button is pressed you set it to 'false'
2. Separately, you blink the LED only if the internal variable is true.

[pablocx]

Hi and thanx for the super fast answer. Internal variables are the ones inside the while loop?

I will try it.
Thanx

[marco_c]

'Internal' as opposed to reading the I/O directly. You can either make it a global variable or declare ir in the loop(), in which case it needs to be static so that it does not get re-initiliased every time through loop().

[pablocx]

Understood!
Thanx.
Will try it and tell you.

Regards

Pablo

[JCA34F]

Change this:

while(digitalRead(buttonBpin) =! LOW){

To:

while(digitalRead(buttonBpin) != LOW){

^
Better:
while(digitalRead(buttonBpin)){ 

[drmpf]

A few of my tutorials you could look at

How to write Timers and Delays in Arduino
Multi-tasking in Arduino
Debouncing Switches in Arduino

[TomGeorge]

Hi,
You need to detect when the buttons are BEING pressed , not pressed.
I think you need in Pseudo Code;

If Button A goes from HIGH to LOW.
Set stateBlink variable HIGH
If stateBlink is HIGH
then Blink
else
don't Blink
If Button B goes from HIGH to LOW.
Set stateBlink variable LOW
code loops back

The thing about this method is you don't need to worry about debouncing.

Tom...

[johnwasser]

const int ledPin = 5;
const int buttonApin = 9;
const int buttonBpin = 8;
const unsigned long interval = 1000;


boolean Blinking = false;
boolean ledState = false;
unsigned long previousMillis = 0;



void setup()
{
  pinMode(ledPin, OUTPUT);
  pinMode(buttonApin, INPUT_PULLUP);
  pinMode(buttonBpin, INPUT_PULLUP);
}


void loop()
{
  if (digitalRead(buttonApin) == LOW)
    Blinking = true;


  if (digitalRead(buttonBpin) == LOW)
    Blinking = false;


  if (Blinking)
  {
    unsigned long currentMillis = millis();


    if (currentMillis - previousMillis >= interval)
    {
      // save the last time you blinked the LED
      previousMillis = currentMillis;


      // if the LED is off turn it on and vice-versa:
      ledState = !ledState;


      // set the LED with the ledState of the variable:
      digitalWrite(ledPin, ledState);
    }
  } // end if (Blinking)
}