[SOLVED]Led changing when press a button

Using Arduino LEDs and Multiplexing
#1

Hi everyone,

I’m want to do a changing led program with Arduino. When the program initiate all leds are off but when you press a button, the first led turn on, If you unpress the bottom the led go off. Then, if you press the button again the second led turn off and when yo unpress the button, it takes off. There are 8 leds and when you get the led number 8, the program will iniciate again. How can I do it?

int leds[] = {0,1,2,3,4,5,6,7};
int boton = 8;
int buttonPushCounter = -1;   
int buttonState = 0;      
int lastButtonState = 0;   
int i = -1;
void setup () {
for (i=-1; i<=7;i++){
pinMode (leds[i],OUTPUT);
}
pinMode(boton, INPUT);
digitalWrite(boton,HIGH);
}
void loop () {
  buttonState = digitalRead(boton);

  if (buttonState != lastButtonState) {
    if (buttonState == LOW) {
       buttonPushCounter++;
      digitalWrite(leds[buttonPushCounter], HIGH);
      digitalWrite(leds[buttonPushCounter-1], LOW);  
     
     while(digitalRead(boton) == LOW)   // when pin goes LOW
         {
            
             digitalWrite(buttonPushCounter, HIGH);     
             // turn on LED
          }
    digitalWrite(buttonPushCounter, LOW); 
    }
    else {
      Serial.println("off"); 
         }
          
  
  }

  lastButtonState = buttonState;
 if (buttonPushCounter % 8 == 0) {
   digitalWrite(leds[0], HIGH);
   buttonPushCounter = 0;
   
  }
 
}

The else statement is crazy but the program works but it dont reset when it release the 8º led. Thanks you :slight_smile:

#2

See the way the code turns into italics? If you read the "How to use the Forum" stick post it will tell you how to post code.

#3

Thanks you :slight_smile:

#4

but it dont reset when it release the 8º led.

Try replacing

buttonPushCounter++;

with

buttonPushCounter = (buttonPushCounter + 1 ) & 0x07;

That will keep it between 0 and 7

As you had it the count could go to 8 then it would do the

digitalWrite(leds[buttonPushCounter], HIGH);

With the index of that array at 8 which is one bigger than the array was defined for. ( don’t forget that array indexes start at zero )
Note that you also use pins 0 and 1 for LEDs. These are best avoided as they are used for downloading code and putting an LED as a load on them might upset downloads.

#5

Grumpy_Mike:
Try replacing

buttonPushCounter++;

with

buttonPushCounter = (buttonPushCounter + 1 ) & 0x0F;

That will keep it between 0 and 7

Did you mean:

buttonPushCounter = (buttonPushCounter + 1 ) & 0x07;
#6

Yes I did sorry. I have corrected it now.

#7

Thanks you for your help. The final code is this:

int leds[] = {0,1,2,3,4,5,6,7};
int boton = 12;
int contadorpulsos = 0;  
int estadoBoton = 0;       
int estadoanterior = 0;   
int i = 0;

void setup () {
  for (i=0; i<=7;i++){
  pinMode (leds[i],OUTPUT);
}
  pinMode(boton, INPUT);
  digitalWrite(boton,HIGH);
}

void loop () {
  estadoBoton = digitalRead(boton);
  digitalWrite(contadorpulsos-1, LOW);
  if (estadoBoton != estadoanterior){
    while(digitalRead(boton) == LOW){
    digitalWrite(contadorpulsos, HIGH);            
          }
    if (estadoBoton == LOW) {
       contadorpulsos = (contadorpulsos + 1 ) & 0x07;
      if (contadorpulsos % 9 == 0) {
        digitalWrite(leds[7],LOW);
         contadorpulsos = 0;
                    }
    digitalWrite(contadorpulsos, LOW); 
    }     
  }
  estadoanterior = estadoBoton;
}
#8

OK but note:-

if (contadorpulsos % 9 == 0)

can only be true when contadorpulsos = 0 so you can change that bit of code to .

      if (contadorpulsos == 0) {
        digitalWrite(leds[7],LOW);
                    }
#9

The code run with and without the note but I think that if you divid contardorpulsos by 0 or 9 (when the variable realease 9), the condition (contadorpulsos % 9 == 0) come true. Thanks you for your supporting.

#10

(when the variable realease 9)

You are not understanding. The variable CAN NEVER reach the value of 9.
The line:-

contadorpulsos = (contadorpulsos + 1 ) & 0x07;

means the value can only reach 7.
See:-
arduino.cc/en/Reference/BitwiseAnd
If you don't believe me then try printing out the value after the increment.

#11

That's right. I add a code to show in serial port the variable and it don't realease 9. But, if you change: contadorpulsos = (contadorpulsos + 1 ) & 0x07; for: contadorpulsos++; it release 9 and, instantly, 0.

#12