555 Falsely triggering from car's ignition system.

[Screech]

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]

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]

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]

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

Thanks

 

[Nigel Goodwin]

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]

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.