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  • arduino best practice
  • arduino circuit
Related

How to configure an Arduino GPIO as an input

colporteur
colporteur over 4 years ago

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.

 

image

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Top Replies

  • baldengineer
    baldengineer over 4 years ago +9
    100K and 47K are very weak pull-down (or up) resistors. If you're in a known noisy environment, you probably want something in the 1K to 4.7K range.
  • wolfgangfriedrich
    wolfgangfriedrich over 4 years ago +8
    Try a small capacitor ( 10nF ) in parallel to the resistor. This is called de-bouncing an input. Can also be done in software, there might even Arduino libraries for that. - W.
  • dougw
    dougw over 4 years ago +7
    It sounds like you are getting cross-talk as well as switch bouncing. If you put a resistor in series with the switch and a capacitor at the digital input as wolfgangfriedrich mentioned, there won't be…
Parents
  • Jan Cumps
    Jan Cumps over 4 years ago

    ... and if you can afford it in your design, polling is more forgiving than triggering.

    Triggers are excellent for digital signals. For mechanical switches they are problematic by design.

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  • Jan Cumps
    Jan Cumps over 4 years ago

    ... and if you can afford it in your design, polling is more forgiving than triggering.

    Triggers are excellent for digital signals. For mechanical switches they are problematic by design.

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