Switches and push buttons: Difference between revisions

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Three methods to wire
Three methods to wire
# External pullup or pulldown resistor: Use <code>pinMode( Button_pin, INPUT);</code> in the setup.
# Internal resistor (20k-50k Ω): Use <code>INPUT_PULLUP</code> in setup <code>pinMode( Button_pin, INPUT_PULLUP);</code>. The default value is <code>HIGH</code> (1) and by pressing the button the state goes to <code>LOW</code>.  
# Internal resistor (20k-50k Ω): Use <code>INPUT_PULLUP</code> in setup <code>pinMode( Button_pin, INPUT_PULLUP);</code>. The default value is <code>HIGH</code> (1) and by pressing the button the state goes to <code>LOW</code>.  
# External pullup or pulldown resistor: Use <code>pinMode( Button_pin, INPUT);</code> in the setup.  
# The bad method: Use <code>pinMode( Button_pin, INPUT);</code> in the setup without any resistors. The default value will float between 0V and 5V: there is no internal or external
# The bad method:
voltage reference for the push button.

Revision as of 12:21, 23 July 2023

Introduction

Theory A: Simple switch

Theory B: Push Button

DPST button and function

A double pole single throw push button micro switch (DPST) is a widely used button. Push button switches are often color coded to indicate their function.

Three methods to wire

  1. External pullup or pulldown resistor: Use pinMode( Button_pin, INPUT); in the setup.
  2. Internal resistor (20k-50k Ω): Use INPUT_PULLUP in setup pinMode( Button_pin, INPUT_PULLUP);. The default value is HIGH (1) and by pressing the button the state goes to LOW.
  3. The bad method: Use pinMode( Button_pin, INPUT); in the setup without any resistors. The default value will float between 0V and 5V: there is no internal or external

voltage reference for the push button.