"LOW" doesnt actually keep the pin off

Forum 2005-2010 (read only) Software Troubleshooting
1

I just recieved my Arduino board so I'm still trying simple stuff, so don't laugh :-/

I was trying to make a led light light up, whenever you press any of the 4 buttons, but when the program starts first there is a weak light, and when I press a button it lights up a little bit brighter. I just dont get it... I tell the board to keep the pin low when there are no buttons pressed. What is the problem?

Here is the code (the buttons are attached to pins 9-12 and the led is on 13):

int ledPin = 13;
int firstPin = 9;
int secondPin = 10;
int thirdPin = 11;
int fourthPin = 12;
int one = 0;
int two = 0;
int three = 0;
int four = 0;
void setup()
*{ *

  • pinMode(ledPin, OUTPUT);*
  • pinMode(firstPin, INPUT);*
  • pinMode(secondPin, INPUT);*
  • pinMode(thirdPin, INPUT);*
  • pinMode(fourthPin, INPUT); *
    }

void loop()
{

  • one = digitalRead(whtPin);*

  • two = digitalRead(bluPin);*

  • three = digitalRead(redPin);*

  • four = digitalRead(yelPin);*

  • if(one == HIGH || two == HIGH || three = HIGH || four = HIGH)*

  • {*

  • digitalWrite(ledPin, HIGH);*

  • }*

  • else { digitalWrite(ledPin, LOW);}*
    }

2

hi

does this actually compile?

one = digitalRead(whtPin);
  two = digitalRead(bluPin);
  three = digitalRead(redPin);
  four = digitalRead(yelPin);

The whtPin, redPin etc variables are not declared anywhere.
Also, do you have pull-up or pull-down resistors on the switches? Without them the input pin values float, and in turn this makes the "if loop" go back and forth, giving you a dim light.

D

3

Also you need two equals signs == not one = for a comparison, the three = HIGH should be three == HIGH, etc.

4

eh... i just changed the variable names so its more understandable here, but it seems that i forgot a few :wink:
and yyes, i does compile... its prolly like Daniel said about the resistors.

Thank you :wink: