How can I detect when a button is pressed using an analog pin instead of a digital pin

[drksoulk]

This my second time making a topic because I put it in the wrong area.

[ep01256]

In the diagram, move the connection from pin 2 to pin A0

void setup() {
  pinMode(A0, INPUT);
}
void loop() {
//if button is tied down to ground
if (analogRead(A0) == 1023) {
  //if button pressed, do code...
}
else {
  //if not pressed, do code...
}
}

[dougp]

If you're talking about using an analog input for the same purpose as you would a digital-only input pin then know the analog inputs A0-A5 on an UNO also function as digital inputs. You set them up and read them just like the other digital pins except substitute Ax for the pin number.

If you mean two or more buttons on an analog input that's a different matter.

[Wawa]

No need for an external resistor if you use internal pull up.
Leo..

void setup() {
  pinMode (A0, INPUT_PULLUP); // switch between pin and ground, NO resistor
}
void loop() {
  if (!digitalRead(A0)) {
    //if button pressed, do code...
  } else {
    //if not pressed, do code...
  }
}

[TomGeorge]

Hi, @drksoulk

What model Arduino, if its a Nano, A6 and A7 do not have internal pullups installed.

Thanks.. Tom...

[ftjuh]

As already mentioned, the correct way is to use digitalRead() and an internal pullup, if available.

If, for some reason, you chose to use analogRead(), this is quite risky:

@ep01256

if (analogRead(A0) == 1023) {

Depending on your connections, the analog value for a button pressed can easily be a bit lower, so it'd be much safer to test against some threshold value:

if (analogRead(A0) > 512) {

[ep01256]

@ftjuh

this is quite risky

Yeah, I didn't think about that. That should work better.