Weird and inexplicable behavior changing HIGH to LOW (PnP video+serial monitor)

Projects Programming
1

My goal is to get a constant 1 when pressing the button.

A) It never prints "noooo" despite the fact it's 0
B) The first time I remove Pin 2, it shows 0. The second time I remove pin 2, it shows constant 1.

Please see video: Youtube Video

int inPin = 2;    // pushbutton connected to digital pin 2
int val;      // variable to store the read value

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

void loop() {
  Serial.println(val);
 val = digitalRead(inPin); 
 if (inPin, HIGH)
 {
  Serial.println("yay");
 }
 if (inPin, LOW)
 {
  Serial.println("nooooo");
 }
 }
2

pinMode(inPin, INPUT) should be pinMode(inPin, INPUT_PULLUP) otherwise when nothing is connected to the pin it will float.

if (inPin, HIGH)? If you are trying to compare the input from inPin this should be if (val==HIGH)

3

You need to learn the fundamentals of the programming language. Start by spending some quality time studying these reference pages:

After that, the problem with your code should be clear.

4

Fair enough, but can you just tell me how come when I press the button it's 0 and when not pressing it's 1? Shouldn't it be the other way around?

5

It all depends on how you have your button wired. Don't make the mistake of thinking HIGH is on and LOW is off. They are just arbitrary states of the pin. They can mean anything you want them to. It's more common for us to wire a button so that when it's closed the input pin state is LOW and when it's open the input pin state is HIGH. The reason is that allows you to use the internal pull-up resistors of the microcontroller instead of needing to add external pull-down resistors to your circuit:

Since HIGH and LOW are just arbitrary pin states What I like to do is define descriptive names for my pin states. Something like this:

const byte buttonPressedState = LOW;
const byte buttonUnpressedState = HIGH;

Then your comparison looks like this:

if(digitalRead(buttonPin) == buttonPressedState) {

Do you see how that code is now self explanatory without even adding a comment? You could forget about that sketch and come back to it after a year and it would still make perfect sense. Whereas with this code:

if(digitalRead(buttonPin) == LOW) {

You might have to spend a little time to figure out what the LOW state indicates.

6

Valeriya:
Fair enough, but can you just tell me how come when I press the button it's 0 and when not pressing it's 1? Shouldn't it be the other way around?

Need a wiring diagram to tell for sure but most physical buttons as well as other devices are wired such that LOW is the "active" state. So, as pert said, don't read much into HIGH and LOW as they are just descriptions of the state of the input.