Problems with INPUT_PULLUP

[davermacleod]

I cannot get yardButtonPin2 to work. it apparently stays HIGH even when its button is pushed the other two buttons work perfectly.

What should I be looking at to fix this.

Railway Yard-Siding Signalling V3.pdf (7.7 KB)

const int sidingButtonPin = 24;  
//number of the siding pushbutton pin 
const int yardButtonPin2 = 33;  
//number of the second yard pushbutton pin
const int yardButtonPin = 26; 
//number of first yard pushbutton pin

pinMode(sidingButtonPin, INPUT_PULLUP); 
 pinMode(yardButtonPin, INPUT_PULLUP);
 pinMode(yardButtonPin2, INPUT_PULLUP);

void loop() {
  // put your main code here, to run repeatedly:

  // check if the siding putton is pressed, if it is, it's LOW
  sidingButtonState = digitalRead(sidingButtonPin);

  // check if the yard putton is pressed, if it is, it's LOW
  yardButtonState = digitalRead(yardButtonPin);
  if (yardButtonState  == LOW) {
    Serial.print("First Yard Button Pressed");
  }
  if (yardButtonState == HIGH) {
    yardButtonState = digitalRead(YardButtonPin2);
    if (yardButtonState == LOW) {
      Serial.print("Second Yard Button Pressed");
    }
  }

  if (sidingButtonState == LOW) {
    //Serial.println("Siding Button Pushed");
    ThrowSidingSwitch();

  }

  if (yardButtonState == LOW) {

    Serial.println();
    Serial.println("Yard Button Pushed");
    ThrowYardSwitch();

  }

[anon73444976]

@davermacleod

What should I be looking at to fix this.

Posting your code.
Posting your schematic

[UKHeliBob]

Check the operation of the button by swapping it for another one. Does the problem follow the button or does it still occur on the same pin ?

I note that YardButtonPin2 is only read if YardButtonPin is currently HIGH. Is that what you intend to happen ?

[LarryD]

Show us a good schematic of your circuit.
Show us a good image of your ‘actual’ wiring.
Give links to components.

[davermacleod]

Found the problem, I have a ground on the Mega that's not working. Moved it to another ground and now it working.