Cannot figure out high input

canthinkofname · April 23, 2024, 12:58pm

  int pinA = 2;
  int pinB = 3;
  int pinC = 4;
  int pinD = 5;
  int pinF = 6;
  int pinG = 7;
  int ledPin1 = 9;
  int ledPin2 = 10;
  int ledPin3 = 11;
  int ledPin4 = 12;

  int pinstateAD = LOW;
  int pinstateAF = LOW;
  int pinstateAG = LOW;
  int pinstateBF = LOW;
  int pinstateBG = LOW;
  int pinstateCD = LOW;
  int pinstateCG = LOW;
void setup() {
  // put your setup code here, to run once:

  pinMode(pinA, OUTPUT);
  pinMode(pinB, OUTPUT);
  pinMode(pinC, OUTPUT);
  pinMode(pinD, INPUT);
  pinMode(pinF, INPUT);
  pinMode(pinG, INPUT);
  pinMode(ledPin1, OUTPUT);


}

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(pinA, HIGH);
  digitalRead(pinD);
  if (pinD == HIGH);  {
    digitalWrite(ledPin1, HIGH);
  }
}

this is my code. I have a wire from digital output pin 2 jumped to digital input pin 5, and no matter what, my ledPin1 turns on. if i disconnect the wire, on. if i change "if (pinD == HIGH)" to low, led on. what am i missing?

UKHeliBob · April 23, 2024, 1:03pm

Welcome to the forum

    digitalRead(pinD);
    if (pinD == HIGH)

You read the state of pinD then ignore it

Then, depending on whether the value (not the state) of pinD is HIGH or LOW you take actions

The value of pinD will always be 5, hence HIGH

Can you see the problem ?

JohnLincoln · April 23, 2024, 1:07pm

In loop() you never do anything to turn ledPin1 LOW.
So if it ever goes high for any reason, it will stay high.

canthinkofname · April 23, 2024, 1:08pm

i have also tried like this

 digitalWrite(pinA, HIGH);
  if (digitalRead(pinD = HIGH))
    ;
  {
    pinstateAD = 1;
  }

I've also tried setup like this, but if you are saying the value of pinD is always 5, why am i reading pinD for HIGH/LOW

canthinkofname · April 23, 2024, 1:11pm

OH i need to set it to low before this, i see. will try and come back

UKHeliBob · April 23, 2024, 1:16pm

if (digitalRead(pinD = HIGH))

Wrong in a different way this time

What is the parameter needed for digitalRead() ?
how do you compare two values ?
Answer, not by using =

canthinkofname · April 23, 2024, 1:16pm

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(ledPin1, LOW);
  digitalWrite(pinA, HIGH);
  if (digitalRead(pinD == HIGH));  {
    digitalWrite(ledPin1, HIGH);
  }
}

light is still on with no connection between pin 2 and 5.

UKHeliBob · April 23, 2024, 1:18pm

if (digitalRead(pinD == HIGH));

Nearly, but the semicolon should not be there because it is the only code dependant on the result of the test

canthinkofname · April 23, 2024, 1:22pm

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(ledPin1, LOW);
  digitalWrite(pinA, HIGH);
  if (digitalRead(pinD == HIGH))  {
    digitalWrite(ledPin1, HIGH);
  }
}

ledPin1 is still on with no connection to pinD.. it only turns off if i change this line

  digitalWrite(ledPin1, HIGH);

to LOW

UKHeliBob · April 23, 2024, 1:24pm

if (digitalRead(pinD == HIGH))

Still wrong

canthinkofname · April 23, 2024, 1:30pm

hmm.. I'm not sure what I'm missing. digitalRead(pinD
should read pin 5 for a high or low.. OH

if (digitalRead(pinD) == HIGH)

is this it? is that what im doing, including the HIGH in the wrong area of of the statement?

UKHeliBob · April 23, 2024, 1:32pm

OH indeed

Yes, the parameter for digitalRead() is a pin number alone

canthinkofname · April 23, 2024, 1:32pm

Hah, you're a good teacher. made me think. thank you.

DaveX · April 23, 2024, 1:35pm

Yes, the pinD == HIGH inside of the parentheses simplifies into:

  pinD == HIGH
  5 == 1
  false
  0

... before digitalRead(???) starts to work with it.

UKHeliBob · April 23, 2024, 1:39pm

I am glad that you appreciate that and that you got there in the end. It would have been easy to give the answer, but maybe by giving you clues and you working it out you will remember it better.

For the benefit of anyone finding this topic at a later date please post your working sketch

canthinkofname · April 23, 2024, 2:09pm

working on it.. it seems i have some other problems with the rest of the code.. i seem to be having problems with my led 3 turning on currently (with everything else commented out, i think i have the same problem across all my logic for LED's)

int pinA = 2; //pinD counterpart (signal)
int pinB = 3; //pinF counterpart (ground)
int pinC = 4; //pinG counterpart (signal)
int pinD = 5;
int pinF = 6;
int pinG = 7;
int ledPin1 = 9;   //pass
int ledPin2 = 10;  //fail signal short
int ledPin3 = 11;  //fail ground short
int ledPin4 = 12;  //no continuity

int pinstateAD = 0;
int pinstateAF = 0;
int pinstateAG = 0;
int pinstateBF = 0;
int pinstateBG = 0;
int pinstateCD = 0;
int pinstateCG = 0;



void setup() {
  pinMode(pinA, OUTPUT);
  pinMode(pinB, OUTPUT);
  pinMode(pinC, OUTPUT);
  pinMode(pinD, INPUT);
  pinMode(pinF, INPUT);
  pinMode(pinG, INPUT);
  pinMode(ledPin1, OUTPUT);
  pinMode(ledPin2, OUTPUT);
  pinMode(ledPin3, OUTPUT);
  pinMode(ledPin4, OUTPUT);
 
}

void loop() {
  digitalWrite(ledPin1, LOW);
  digitalWrite(ledPin2, LOW);
  digitalWrite(ledPin3, LOW);
  digitalWrite(ledPin4, LOW);
 

  digitalWrite(pinA, HIGH);
  if (digitalRead(pinD) == HIGH)
  {
    pinstateAD = 1;
  }
  /*if (digitalRead(pinF) == HIGH)
  {
    pinstateAF = 1;
  }*/
  if (digitalRead(pinG) == HIGH)
    
  {
   // pinstateAG = HIGH;
  }
  digitalWrite(pinA, LOW);
  digitalWrite(pinB, HIGH);
  if (digitalRead(pinF) == HIGH)
  {
    pinstateBF = 1;
  }
  if (digitalRead(pinG) == HIGH)
  {
    pinstateBG = 1;
  }
  digitalWrite(pinB, LOW);
  digitalWrite(pinC, HIGH);

  if (digitalRead(pinD) == HIGH)
  {
    pinstateCD = 1;
  }
  if (digitalRead(pinG) == HIGH)
  {
    pinstateCG = 1;
  }
  digitalWrite(pinC, LOW);

  if (pinstateAD == 1) {
    if (pinstateAG ==1) {
      digitalWrite(ledPin2, HIGH);
    }
  }
  if (pinstateAF == 1); {
    digitalWrite(ledPin3, HIGH);
    }
  /*if (pinstateAD == pinstateAG == 0); {
    digitalWrite(ledPin4, HIGH);
    }*/
  /*if (pinstateBF = 0); {
    digitalWrite(ledPin4, HIGH);
    }*/
  if (pinstateBG == 1); {
    digitalWrite(ledPin3, HIGH);
    }
  /*if (pinstateCD == pinstateCG == 1); {
    digitalWrite(ledPin2, HIGH);
    }*/
  /*if (pinstateCD == pinstateCG == 0); {
    digitalWrite(ledPin4, HIGH);
    }*/
  if ((pinstateAD != pinstateAG) && (pinstateCD != pinstateCG) && (ledPin2, ledPin3, ledPin4 = 0));{
    digitalWrite(ledPin1, HIGH);
    }
}

please bear with me, i just started trying to learn this language like 12 hours ago.

canthinkofname · April 23, 2024, 2:11pm

  digitalWrite(ledPin3, HIGH);

im assuming this is another syntax mistake in these lines.
pinA and pinF are not connected. Nor are pin B and G, but if comment those 2 out the led turns off.

UKHeliBob · April 23, 2024, 2:16pm

I have had a very short look at your code and noticed this immediately

  if (pinstateBG == 1); {
    digitalWrite(ledPin3, HIGH);
    }

That semicolon should not be there. Because it is there the digitalWrite() is executed unconditionally whatever the value of pinstateBG

I did not look any further

canthinkofname · April 23, 2024, 2:51pm

Ah. yeah that seems to keep getting me. You are right. i've cleaned it up, and for sake of simplicity decided to cut out the extra LED's and stick with pass/fail. this is the program working now i believe.

int pinA = 2;  //pinD counterpart (signal)
int pinB = 3;  //pinF counterpart (ground)
int pinC = 4;  //pinG counterpart (signal)
int pinD = 5;
int pinF = 6;
int pinG = 7;
int ledPin1 = 9;   //pass
int ledPin2 = 10;  //fail signal short  (any fail until pin3 and 4 are written into fail modes)
//int ledPin3 = 11;  //fail ground short
//int ledPin4 = 12;  //no continuity

int pinstateAD = 0;
int pinstateAF = 0;
int pinstateAG = 0;
int pinstateBF = 0;
int pinstateBG = 0;
int pinstateCD = 0;
int pinstateCG = 0;
int passState = 1;



void setup() {
  pinMode(pinA, OUTPUT);
  pinMode(pinB, OUTPUT);
  pinMode(pinC, OUTPUT);
  pinMode(pinD, INPUT);
  pinMode(pinF, INPUT);
  pinMode(pinG, INPUT);
  pinMode(ledPin1, OUTPUT);
  pinMode(ledPin2, OUTPUT);
  // pinMode(ledPin3, OUTPUT);
  //pinMode(ledPin4, OUTPUT);
}

void loop() {
  digitalWrite(ledPin1, LOW);
  digitalWrite(ledPin2, LOW);
  //digitalWrite(ledPin3, LOW);
  //digitalWrite(ledPin4, LOW);


  digitalWrite(pinA, HIGH);
  if (digitalRead(pinD) == HIGH) {
    pinstateAD = 1;
  }
  if (digitalRead(pinF) == HIGH) {
    pinstateAF = 1;
  }
  if (digitalRead(pinG) == HIGH)

  {
    // pinstateAG = HIGH;
  }
  digitalWrite(pinA, LOW);
  digitalWrite(pinB, HIGH);
  if (digitalRead(pinF) == HIGH) {
    pinstateBF = 1;
  }
  if (digitalRead(pinG) == HIGH) {
    pinstateBG = 1;
  }
  digitalWrite(pinB, LOW);
  digitalWrite(pinC, HIGH);

  if (digitalRead(pinD) == HIGH) {
    pinstateCD = 1;
  }
  if (digitalRead(pinG) == HIGH) {
    pinstateCG = 1;
  }
  digitalWrite(pinC, LOW);

  if (pinstateAD == 1) {
    if (pinstateAG == 1) {
      digitalWrite(ledPin2, HIGH);
    }
  }
  if (pinstateAF == 1) {
    digitalWrite(ledPin2, HIGH);
    (passState = 0);
  }
  if (pinstateAD == 0) {
    if (pinstateAG == 0) {
      digitalWrite(ledPin2, HIGH);
      (passState = 0);
    }
  }
  if (pinstateBF = 0) {
    digitalWrite(ledPin2, HIGH);
  }

  if (pinstateCD == pinstateCG == 1) {
    digitalWrite(ledPin2, HIGH);
    (passState = 0);
  }
  if (pinstateCD == 0) {
    if (pinstateCG == 0) {
      digitalWrite(ledPin2, HIGH);
      (passState = 0);
    }
  }
  if (passState == 1) {
    digitalWrite(ledPin1, HIGH);
  }
}

UKHeliBob · April 23, 2024, 3:46pm

    if (pinstateBF = 0)

Perhaps not

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Cannot figure out high input

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