Pin interference

Hi,
New to this forum so I hope this is the correct place to ask for help.
I have searched, both inside and outside of this forum but can't find anything to help me.

My setup is located in my car

My problem is that I have a HAM-radio close to the arduino ( about 50cm) and when I set the radio to transmit at >30W, one or more pins on the arduino goes high and triggering my system.

I have a pulldown resistor at 10K on each pin but that doesn't help.

Is there a way for me to shield the arduino from this interference?

The systems share a 12V-line but have there own grounds to the battery.

0 amgalbu over 9 years ago

Hi Niclas
I don't know the connection layout of the Arduino board, but I think you could try to put the Arduino board inside e metallic case and connect the case to the ground, This couls help in shielding Arduino baord from induced interferences
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0 jw0752 over 9 years ago

Hi Niclas,
It would be a good idea to have a decoupling capacitor on the power wire close to the arduino, Also you can try using shielded cable on your input lines to the arduino. Depending on the sensors or inputs of your system you could also try lowering your pull down resistors and put decoupling capacitors on the inputs as well.
John
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0 mcb1 over 9 years ago

one or more pins on the arduino goes high and triggering my system.

Do you know if the pins are used within the program.?

As jw0752 has suggested I suspect you might be getting spikes up the 12v line.
Arduino have some filtering but in reality it is minimal and since a vehicle delivers 14.2v when running, it is operating at the limits of the regulator.
For my automotive application I used an 8v regulator prior to the on-board 5v, and you could apply filtering there.

A simple check could be powering the Arduino from another source.

The inputs on Arduino are very high impedance, so your precaution of pulling down the inputs with a 10k is good, but your external connections may be picking enough RF to overcome this.

Mark
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0 Robert Peter Oakes over 9 years ago

You could also try placing a very small value cap on the pins to ground, perhaps 50pF ish, this would present a short to RF but not tot the real control signals, though I think a slightly more elabourate filter may be better, if you have them, a small inductor in series with the input pins or loop the wires through a ferrite core
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0 mcb1 over 9 years ago in reply to Robert Peter Oakes

We are assuming the problem is coming in the inputs.

Perhaps bellator could include the code for the Arduino, and maybe the connections, and we could help isolate it.

Mark
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0 Robert Peter Oakes over 9 years ago in reply to mcb1

True, a few photos, the schematic and code would be a great help
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