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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…
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  • wolfgangfriedrich
    wolfgangfriedrich over 4 years ago

    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.

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  • colporteur
    colporteur over 4 years ago in reply to wolfgangfriedrich

    Thanks DW. I understand the goal of de-bounce. I haven't had to use the technique with Pi's and for the most part with the Arduino. I'm thinking it has to do with motors and relays I have started to deploy. I see on the Arduino site there is a de-bounce sketch to eliminate the issue.

     

    I will give both solutions a try. I'm looking for consistent. Maybe the component is best.

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  • colporteur
    colporteur over 4 years ago in reply to wolfgangfriedrich

    Thanks DW. I understand the goal of de-bounce. I haven't had to use the technique with Pi's and for the most part with the Arduino. I'm thinking it has to do with motors and relays I have started to deploy. I see on the Arduino site there is a de-bounce sketch to eliminate the issue.

     

    I will give both solutions a try. I'm looking for consistent. Maybe the component is best.

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