simple button request / led activation doesn't work

Projects General Guidance
1

Hey there [=

I just started using arduino, and successfully applied the date-reset workaround for making my arduino uno [smd edition] work with my windows 8 laptop. I'm using a german book called "prototyping interfaces" and downloaded code and electronic assembly instructions from the related webpage www.prototypinginterfaces.com

Every time I upload a sketch to the board, the compiling takes one or two minutes and I get the following error message:

Couldn't determine program size: null

I don't know if this is relevant for my problem, but I wanted to post it anyway. The 'Hello World' blinking sketch worked fine, so I suppose it's no real problem.

Now this is the code I downloaded:

// global variables

// Button attached to pin 2
int ButtonPin = 2;
// LED attached to pin 13
int LEDPin =  13;
// current status of button
int ButtonState = 0;

void setup() 
{
  // initialize LEDPin as OUTPUT:
  pinMode(LEDPin, OUTPUT);      
  // initialize ButtonPin as INPUT:
  pinMode(ButtonPin, INPUT);     
}

void loop()
{
  // write value from ButtonPin into ButtonState
  ButtonState = digitalRead(ButtonPin);

  // if ButtonState is HIGH
  if (ButtonState == HIGH) 
  {     
    // LED = ON    
    digitalWrite(LEDPin, HIGH);  
  }
  // if ButtonState is LOW
  else 
  {
    // LED = OFF
    digitalWrite(LEDPin, LOW); 
  }
}

and this is the electronic assembly:

Instead of turning on when the button is pressed, and off when the button isn't pressed, the LED just blinks two times short, waits a second, then turns on for around a minute, then repeats all this. It doesn't react at all to the button. I also rotated and exchanged the button for another one, but nothing changed.

Maybe it's just a stupid mistake, but I can't make it out and also did not find anything with google, so maybe someone can help. thanks!

2

Change this line:

pinMode(ButtonPin, INPUT);

To this:

pinMode(ButtonPin, INPUT_PULLUP);

And the switch wiring as shown below.

SimpleSwitch.jpg

3

Now it just blinks every one or two minutes and still doesn't respond.

After I removed the resistor and connected the other side of the switch [where the red cable is connected in the graphic I posted] to GND, it works inverted. So the LED turns off when I press the button. It still does this doubleblink-one second pause- thing every one or two minutes.

4

With the code you posted, the LED can never blink.
Yes it works inverted as the input is now active low.
If you want the LED to come on with a button press, change as follows:

 // if ButtonState is HIGH means not pressed
  if (ButtonState == HIGH) 
  {     
    // LED = OFF    
    digitalWrite(LEDPin, LOW);  
  }
  // if ButtonState is LOW means pressed
  else 
  {
    // LED = ON
    digitalWrite(LEDPin, HIGH); 
  }

Get that going first, and you can then add switch debouncing later.

5

You're missing a resistor in the LED circuit.
You're using Pin 13 which has an onboard LED. This may be interfering with your LED. Try using a different pin for your LED.