How do you wire momentary switches with only two poles

[barrychapman]

I am trying to wire up several momentary switches - but these only have two poles:

I have one pole going to the PIN5 (digital input) on the arduino, and the other going to the +5V line.

Where do I wire ground to with the 10K pulldown resistor? I was able to make this work with a tactile push button but that had 4 legs, so I am unsure what to do here. I am not an electrical engineer by any stretch of the imagination - so pardon my ignorance.

Thanks!

[jfjlaros]

Wire it to ground and use the internal pull-up resistor.

pinMode(5, INPUT_PULLUP);

[barrychapman]

The internal pullup was giving me unpredictable results, is there a way to do it with the pulldown?

On that tactile switch, that is effectively still a two pole switch right? It just has two pins for each pole

[jfjlaros]

@barrychapman

unpredictable results

That is probably because of bouncing. Have you tried to use a button library?

https://www.arduino.cc/reference/en/libraries/ebutton/

[barrychapman]

I am pretty new to the arduino stuff - i am not using a button library that i know of

[jfjlaros]

Adapted from the link in post #4:

#include "Arduino.h"
// 1. Include the library
#include "EButton.h"

// 2. Instantiate the object and attach it to PIN 5
EButton button(5);

// 3. Handler method for a single-click
void singleClick(EButton &btn) {
	Serial.println("We have a single-click!");
}

void setup() {
	Serial.begin(115200);
// 4. Attach the handler
	button.attachSingleClick(singleClick);
	Serial.println("\nClick or double-click!");
}

void loop() {
// 5. Tick the object in a loop
	button.tick();
}

[PerryBebbington]

I think this will answer most of your questions about connecting buttons of all kinds:

Buttons and other electro-mechanical inputs (introduction)

Intended audience This tutorial is intended for people who have mastered the basics of electronics and C/C++ programming. If you are a beginner and find the concepts difficult, please review the basic examples in the Arduino IDE. In this tutorial BUTTON will be a generic term for any kind of switch or other input device with mechanical contacts. Introduction A common requirement in many projects is to have push buttons, switches or other electro-mechanical devices connected as inputs to an A…

To be clear, it applies to what you have, not just the tactile buttons I've used to illustrate things.

[LarryD]

Wire switches as S3 is wired below.

A LOW on the input pin indicates the switch is closed.

[cattledog]

@barrychapman

The internal pullup was giving me unpredictable results,

Can you explain more about what you were experiencing with INPUT_PULLUP? What code were you running?

[herbschwarz]

Maybe those switches do not make good contact a very low current flow, not dry circuit type, but are designed for switching higher currents.

[barrychapman]

Thank you, this clarifies things a lot

[anon44338819]

If using INPUT_PULLUP, then use this wiring configuration:

• Terminal 1 to Pin 5
• Terminal 2 to GND'
  and use pinMode(5, INPUT_PULLUP); in the setup() function.

If not, use this wiring configuration:

• Terminal 1 to Pin 5
• 10K pulldown resistor from Terminal 1 to GND
• Terminal 2 to +5V

Reffer to @LarryD's chart

[b707]

@barrychapman

have one pole going to the PIN5 (digital input) on the arduino, and the other going to the +5V line.

Where do I wire ground to with the 10K pulldown resistor?

To the same pole as arduino PIN5.
In the picture your button has screw terminals so you can easily connect two wires to one pole