next topic »

[on:]

Greetings,
        New guy here, so first things first. Hello! 

        I picked up a Arduino Uno yesterday. So far I've been having a lot of fun messing around, trying to get feel for the basics. I didn't suspect it would be so addicting.

       I'm trying to make a small led light show for my first project but I'm having problems with digitalRead. The layout is very basic right now as I'm trying to plan. So I have two separate circuits. The button circuit from 5v to GND, which is the input when pressed. The other circuit is a simple led (pin 13, resistor, GND).

        The Serial Monitor is displaying 1's & 0's randomly when the button is off resulting in a low flicker of the led. Then all 1's when it is pressed, which is correct.

        In all honestly, I don't know if this is a programming or hardware issue. I've been trying different arithmetic to make it all 0's/off but to no avail (= 0 LOW, = 1 HIGH). If you have any suggestions they would be much appreciated.

Code:

//

int led = 13;
int in = 2;

void setup()
{
  Serial.begin(9600);
 
  pinMode(led, OUTPUT);
  pinMode(in, INPUT);
}

void loop()
{
  int state = digitalRead(in);
  Serial.println(state);
  delay(1);
 
  if (state > 0)
  {
    digitalWrite(led, HIGH);
  }
 
  else (state < 0);
  {
    digitalWrite(led, LOW);
  }
}

[Reply #1 on:]

Greetings,

The Serial Monitor is displaying 1's & 0's randomly when the button is off resulting in a low flicker of the led.

The pin is "floating".  You need a "pull down" (aka "pulldown") or "pull up" (aka "pullup") resistor.  Tutorial explaining...

http://www.ladyada.net/learn/arduino/lesson5.html

[Reply #2 on:]

It sounds like the input pin is floating.
Try this

Code:

  pinMode(in, INPUT_PULLUP);

It will keep the input HIGH when the button is not pressed.  Arrange your circuit to connect the pin to GND when the button is pressed

[Reply #3 on:]

The button circuit from 5v to GND,

If you actually did that you would short out the power supply.

My take on inputs:-
http://www.thebox.myzen.co.uk/Tutorial/Inputs.html

[Reply #4 on:]

My write-up on handling switches:

http://www.gammon.com.au/switches

[Reply #5 on:]

WOW! quick to respond!

The button circuit from 5v to GND,

If you actually did that you would short out the power supply.

My take on inputs:-
http://www.thebox.myzen.co.uk/Tutorial/Inputs.html

Yeh, typo. It was supposed to be 5v > Button > Input Pin.

My write-up on handling switches:

http://www.gammon.com.au/switches

That's amazing! I'm getting solid numbers between states now after using the resistors.

It was the internal resistor on digital side GND that was throwing me off. As when I used it in the tutorials, but on my project I used the power side GND's.

Thanks for the advice and resource share Nick!