my pins give me 1 all the time !

Using Arduino Installation & Troubleshooting
#1

Hi, I got my first arduino uno last week. I had a problem and I thought it's because of bouncing but It's getting so annoying can anyone help me.

here is the problem :

I made the switch circuit with 2 wires and with a 10K resistor . The diagram is like this

http://www.codeproject.com/KB/system/Interfacing_Arduino_LCDs/PushButtonSchematic.png

except there is not 100ohm resistor.

when I connect the wires I should see 1 on the serial monitor and when I disconnect them 0 . but it’s always 1 ! when I connect the wires i it goes to 0 and 1 for a couple of times and then it becomes 1. when I disconnect it it stays at 1 for a a few seconds and it goes to 0 sometimes and sometimes doesn't.

this the simple program that I wrote to light a led when the switch is pushed is like this: //

define enc 8

define led 13

int count = 0 ;

void setup()

{ pinMode(enc,INPUT); pinMode(led, OUTPUT); Serial.begin(9600); }

void loop() { int val = digitalRead(enc); if (val ==HIGH) { digitalWrite(led,HIGH); Serial.println(val); } else{ digitalWrite(led,LOW); } }

I thought maybe it’s because of bouncing. because it was like this since the first day that I got the Arduino. but today I had problem in counting pulses from encode and I was told it's because of my pins has problem. there any other way to check the pins ? it’s UNO btw.

can anyone help me ?

#2

could be that your only writing to the serial monitor when (val ==HIGH)

#3

right, I should put the Serial.print out of the if statement .

but the problem is when the wires are not connected, I still get 1 which is weird. it should be 0 .

#4

nathan_kia: right, I should put the Serial.print out of the if statement .

but the problem is when the wires are not connected, I still get 1 which is weird. it should be 0 .

Or put a print statement in the "else" clause of your if-statement, otherwise you only print when it is high.

#5

None of your image links work.

If you click "additional options" you can attach pictures in the post editor.

#6

I made the code simpler .

int button = 12; 

void setup()
{
    pinMode(button,INPUT);
    Serial.begin(9600);

}

void loop()
{
  int val = digitalRead(button);
  Serial.println(val);
}

when I upload the program, I get the bunch of zeros which is normal

when i connect the wire I get 1, which is normal.
but when disconnect the wire, I get 1 for almost 5 seconds and then the value starts to bounce between 0 and 1 for 3 4 more seconds and then it goes to zero.

one other thing which seems weird is when I place a wire which is connected to nowhere to the pin 12. I get the uploaded picture number 1 !!! and when I take it out, for couple of seconds I get picture number 2. and then it goes to all zero.
it’s so weird. the wire is connected to nowhere !!!

1.png

2.png

#7 
void loop()
{
  int val = digitalRead(button);
  Serial.println(val);
  delay(10); //I bet that cures the problem.
}
#8

As written, there is nothing to make the pin go High once the connection to Ground is released.

Do this instead:

void setup()
{
    pinMode(button,INPUT);
    digitalWrite (button, HIGH); // turns on internal pullup resistor
    Serial.begin(9600);

}

Now val will reliably = HIGH immeditately whenever the switch is not pressed, and LOW when it is pressed.

#9