push button

Projects General Guidance
1

Hello,

I am trying to understand the push button implementation. https://www.arduino.cc/en/tutorial/button

The schematic is the following:

Here is my question. Can I do something more simple like :

Thanks for your answer !

rocky2019

2

Yes, the second approach is preferred.
Just remember to use pinMode(pin, INPUT_PULLUP), and remember that a value of LOW means that the button is pressed.

This is what's going on under the hood:

As you can see, when the switch is open, the pin is at a high voltage (through the resistor built-in to the Arduino), and when the switch is closed, the pin is pulled down to ground (low voltage).

Pieter

3

I understand what you are saying, thank you for the tip !

Are there pull-up resistors on all pins ? I am using the arduino pro mini.

4

rocky2019:
Are there pull-up resistors on all pins ? I am using the arduino pro mini.

Yes, on all pins, except A6 and A7.
(Note: even though A0-A5 are labeled as analog pins, they are full-fledged digital pins as well, so they also have a pull-up resistor. A6-A7 are analog only, so no pull-up.)

5

Great! Thanks for the help !