How to do a RF filter for my RPM sensor

[djatila666]

Hello,

I built a RPM sensor for my DLE ignition.
I'm connecting PIN D8 of my arduino directly to DLE ignition. It works correctly, but I'm worried about RF interferences.

I've seen another post, but no-one has tried it yet and I don't know if it would work.

viewtopic.php?f=86&t=5906

If RF is a problem I would suggest you try to put the 100p (or so) in the location shown in this modified version. That will roll off frequencies above about 34KHz
Edit: I rearranged the buffer so that it could work with external hall sensor as well. In my case I have only a TTL level output from esc to worry about but hall sensors are often open collector so this circuit should work for both but I haven't tested.

Has someone built one that works? If not, any ideas on how to build a RF filter for those interferences I'm concerned about?

Thank you a lot for helping me and sorry for my English, not my main language

[tonnie78]

I gave a simular rpm sensor in combi with an NGH GF38.

No rf filter, never had a problem

[djatila666]

Thanks for your answer.

Another question I have is if the pin d4 you connect directly to the sport?
(My arduino mini pro is 5v)

[tonnie78]

Yes The output from Arduino to S.port is a direct connection