nanoDLP

nmitchko

Member

Registered: 2020-12-11

Posts: 1

Simple question -- How do I wire a limit switch to gpio?

Hi all,

I am trying to connect my 2 limit switches to the NanoDLP 2.2 shield.

Each limit switch is wired with the NC,NO,and C pins. My NanoDLP shield has three pins, a gpio (bridged to the 5v with a 20kohm resistor), gnd, and +5v

How do I match the limit switches to the pins?
-- C -- NO -- NC --
to
-- gpio -- GND -- +5v --

thanks in advance for any help!

bigfilsing

Member

Registered: 2016-11-20

Posts: 306

Re: Simple question -- How do I wire a limit switch to gpio?

Hi
So what youre seeing is your GPIO signal held high to 5 volts .  Its generally speaking bad practice to leave any signal "floating"
From that we can conclude the GPIO needs pulling low in order to register the switch activated
So you only need 2 wires / terminals
C=GND
NO=GPIO

So when the switch is pressed the NO ( normally open) contact will close to ground.