How to eliminate the VFD noise affecting digital sensor reading?

Using Arduino Project Guidance
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I have a problem getting correct readings from a 5v digital sensor connected to an Arduino Uno board. I get correct reading until I start the VFD that drives a 3-phase motor. The sensor reading then becomes illogically wrong! until I stop the VFD again. I tried using a 100nf decoupling capacitor just before the Arduino input pin but it didn't help. I can't change or

The Arduino is powered by a buck converter, which is powered by a power supply that shares the same main with the VFD and I can't change that. The system is grounded, and I can't change any wires unfortunately.

How can I get rid of this interference?

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The very first thing is to physically distance the sensor as far as possible from the VFD.
Second is to use shielded wire connecting the sensor and the Arduino, with the shield connected to ground at the Arduino. The other end of the shield must be left with no connection.
Third is to shield the sensor and connect the shield to the wiring shield.

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Try a bigger cap (on the input pin)?

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I moved your topic to an appropriate forum category @shamooooot.

In the future, please take some time to pick the forum category that best suits the subject of your topic. There is an "About the _____ category" topic at the top of each category that explains its purpose.

This is an important part of responsible forum usage, as explained in the "How to get the best out of this forum" guide. The guide contains a lot of other useful information. Please read it.

Thanks in advance for your cooperation.

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Hint the longer the wire the better antenna it is for EMI.

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This is perfectly normal and the interference is coming from the three phase motor rather than the motor driver.

That is indeed unfortunate because that means you can't fix it. So you may as well throw it in the trash.

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