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How to configure an Arduino GPIO as an input

colporteur

What would you recommend to reduce the spurious triggers on the input of a Nano?

 

Up to now I have been using Arduino Nano microcontrollers for animation support on a model railroad without issue. With the recent completion of the airport scene, I started to experience issues of Nano's receiving spurious triggers. At first I thought maybe I set the input resistor to high, so I reduced the value from 100K to 47K. I got some relief but it has recently raised it ugly head again. Without the resistor the triggering is unpredictable.

 

Currently there are 5 animations that have button control.

  • Aircraft landing simulation (LED)
  • Hanger building Lighting (LED)
  • Simulate arc welder at bench (LED)
  • Compound gate open/close (28BYJ-48 ULN2003 controller)
  • Hanger aircraft engine startup/shutdown (L293 brushless motor)

 

The compound gate sometimes triggers the Hanger aircraft engine animation and vise versa. The input circuit I am using for the Nano is minimal.  These two animations did share the same twisted pair from the button panel. I have separated the animations button to different pairs and I have some relief. I'm thinking maybe there is a simple way to dampen inputs so they are not as sensitive?

 

I'm hoping someone might have a suggestion/best practice recommendation for connecting inputs, that is designed to eliminate the problem.

 

Parents

  •   Can youi feel the amount of pain that I AM IN???  please don't use any silly software, don't use waits. please see my blog NexGen: Fuel Load Indicator: Aftermath!  This shows you how to debounce your switches in hardware.  so how many switches are you going to look at?? after the Schmitt Trigger with its rc network its output should just go the  Arduino's GPIO pin. but wait also attached is a input to N-wat Or gate the output goes to your interrupt line.  This works very well for a rotory swich as well but the switch goes into a 7 to BCD priority encoder. the outputs go the the gpios and the encoders active line goes to the interupt line.

    at this point all you have to do is to read the 3 bits to determin witch switch. (also explanded in the Blog.)

    ~~

    happy laddings..LOL

    Cris

  • in reply to phoenixcomm

    Much appreciate the input CH. I like the Schmitt trigger circuit. {Crap more stuff to add.}

     

    The jury is still out on my direction. A Nano circuit that has been in for months with no issue false triggered the other day. No one was near it and best I can tell nothing switched on or off in the environment. This Nano circuit is constructed the same as all the other. I had never gotten a false trigger on it but then it happened.

     

    I would not expected this issue being that I have deployed physical pull-down resistors. I need to find the source that is causing the triggers. Damn... I could really use the scope I donated to the Collage about now.

  • in reply to colporteur

      Sean,  {Crap more stuff to add.} Duh, for 6 switches its only 6 more resistors, 6 more caps, and one Hex Schmitt Trigger. and that's only 12 more parts + the IC plus you will need the pull-up resistor anyway. You can get a small PCB made for a few bucks. and stuff it yourself. Basically with ANY SWITCH PUSHBUTTON or ROTARY, or THUMBWHEEL SWITCHES WILL ALWAYS GIVE YOU A BOUNCE OR TWO!!! get over it. its life.  If you assume you are not going to get a bounce you most likely will. So err on the side of caution and always debounce them FIRST!

    ~~

    Cris

     

    Sorry for the CAPS but I needed to get your attention.

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  • in reply to colporteur

      Sean,  {Crap more stuff to add.} Duh, for 6 switches its only 6 more resistors, 6 more caps, and one Hex Schmitt Trigger. and that's only 12 more parts + the IC plus you will need the pull-up resistor anyway. You can get a small PCB made for a few bucks. and stuff it yourself. Basically with ANY SWITCH PUSHBUTTON or ROTARY, or THUMBWHEEL SWITCHES WILL ALWAYS GIVE YOU A BOUNCE OR TWO!!! get over it. its life.  If you assume you are not going to get a bounce you most likely will. So err on the side of caution and always debounce them FIRST!

    ~~

    Cris

     

    Sorry for the CAPS but I needed to get your attention.

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