Back to basics with buttons (floating pin problems)

[Dan_ce]

I'm coming back to arduinos after years of using esp32s of various types. With those, I'm used to just connecting one leg of a button to ground and the other to a digital pin. Works fine. Sometimes I use the built in pull up resistor or sometimes I add an external pull up or pull down one.

WIth Arduino, when I've tried doing this, I've ended up with a floating pin. Looking at diagrams, it seems with arduinos they almost always show one leg of the button connected to 5v as well...

Can it be that it's more complicated to wire up a button to an arduino and not have it float?! (I WAS using an external 10K pull down resistor, I had one leg of my button connected to ground but via a 10K resistor. The other leg was just pulled straight into a digital read pin. The only time the read was stable was when the button was being pushed otherwise it was just floating 010101010101010100111000101010101

But am I going mad?? Why would this be very doable on an ESP32 but not on an Arduino?

Am I missing something? Should I take a nap? Get back to my bath chair?

[LarryD]

So there is no confusion, show us a schematic of how the inputs are wired.

[oldcurmudgeon]

See pinMode() - Arduino Reference

Use INPUT_PULLUP so the pin isn't floating. The default is INPUT which floats.

[Dan_ce]

@oldcurmudgeon

Use INPUT_PULLUP so the pin isn't floating

Huh? That’s confusing. You read that I’m using an external pull up?

[Dan_ce]

@LarryD

show us a schematic of how the inputs are wired.

Will do

[PaulRB]

@Dan_ce

With those, I'm used to just connecting one leg of a button to ground and the other to a digital pin

It's just the same with Arduino.

@Dan_ce

WIth Arduino, when I've tried doing this, I've ended up with a floating pin.

You must have made some other mistake.

@Dan_ce

with arduinos they almost always show one leg of the button connected to 5v as well...

That's because most of those diagrams were drawn by beginners who can't get their heads around a pin reading LOW instead of HIGH when the button is pressed, or don't know about internal pull-ups.

@Dan_ce

I WAS using an external 10K pull down resistor, I had one leg of my button connected to ground but via a 10K resistor. The other leg was just pulled straight into a digital read pin. The only time the read was stable was when the button was being pushed otherwise it was just floating

Sounds like you didn't enable the internal pull-up. The 10K was doing nothing useful.

[build_1971]

Maybe an unnecessary question...

A button has 4 pins. Are you aware that it really is 2 sets of pins interconnected inside the button? Always connect them diagonally.

[Dan_ce]

yeah the pcb micro push buttons do have four pins, most (all?) of the ones I'm using have two pins.

But yes I'm aware they're interconnected along the direction of the 'straight' pins - but really appreciate you mentioning it!