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555 Falsely triggering from car's ignition system.

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Screech

New Member
:( When the circuit is near any part of my cars High-Voltage ignition system, it will falsely trigger.

I had the Infra red components mounted inside the distributor.
How do I fix the false triggering?

Thanks
Screech
 

Nigel Goodwin

Super Moderator
Most Helpful Member
There's a lot of electrical rubbish flying about in a car - you need to filter the incoming supply particularly well, and fitting the project in a screen box is desirable. Also screen the leads the the sensor, and keep them as short as possible.
 

Screech

New Member
Oh, Didn't think about that. I'll try it ,Thanks Nigel.

But how to screen the sensors(maybe wont nead to).
Maybe relocate them.

Thanks again.
 

Screech

New Member
Nigel,What do you mean by filtering the supply?
You mean the 12Volt supply?
If so, how do I do that?

Thanks :)
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Screech said:
Nigel,What do you mean by filtering the supply?
You mean the 12Volt supply?
If so, how do I do that?

Thanks :)
For in-car electronics it's a big subject :).

First off I would use a voltage regulator to feed the circuit, dropping the supply to 9V or 6V through a regulator would remove a lot of PSU noise. Then feed that from the 12V car supply through a low-pass filter, with a series choke and capacitors down to ground on both sides.

On thing you might try first, running it off a totally separate supply, use an external dry battery to power it, and see if it helps.
 

Screech

New Member
I did try a seperate supply and it did not help.

ok, I'll shield everything this time, and use a voltage regulator.
i may also try a high quality audio type car noise filter, as I'm not familiar with filtering.
ta once again. :)
 
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