Hi guys,

This is my first post so apologies if im not very clear on what im after.

This project is for a car, and I need a type of switch/circuit. Basically I want to earth the signal in one cable, when another separate cable is also earthed. The state of the "signal" earth constantly changes, so the switch needs to be fast if possible to be able to match the state.

The voltages of the 2 cables are totally different and can not be mixed (if that makes sense)

Sorry if thats really badly worded, and thanks for any help.

 

Can you please clarify if this is a modification of a normal car or an offroad vehicle? Automotive modifications are unfortunately not allowed to be discussed on AAC.

 

Can you please clarify if this is a modification of a normal car or an offroad vehicle? Automotive modifications are unfortunately not allowed to be discussed on AAC.

I think he states right in the beginning "This project is for a car." I'm afraid you're right, in that AAC strictly forbids discussions of automobile modifications and/or repairs. A warning to the OP: Don't be offended if this thread is closed. It is an issue of safety that we do not talk about car mods here, so hopefully you'll understand.

Regards,
Der Strom

 

Its for a track car Using an Omex rev limiter on bike carbs (which would mean the car wouldnt be road legal, wouldnt pass MOT for emissions)

The worst as far as safety is concerned, is that the ignition signal from the dual coil pack would earth, and the engine would cut out. No risk of fire, it isnt HT voltage, just a 0.3v signal and a -12v at minimal ampage.

Hope this means you can answer my question It wouldn't really call it a modification, its merely a means of opening a switch.
If I dont find an answer, I think I might go mad

 

A solid state relay or optorelay can probably easily do this, but without actually knowing what the trigger signal looks like (current it can provide, voltage level and polarity, are transients present and what is their voltage level) it's hard to suggest something.

Also, the current to be switched needs to be known.

 

A solid state relay or optorelay can probably easily do this, but without actually knowing what the trigger signal looks like (current it can provide, voltage level and polarity, are transients present and what is their voltage level) it's hard to suggest something.

Also, the current to be switched needs to be known.

I will have to get back to you on that one. They arent things I know off hand, but can easily find out. It cant provide much current, because this would interfere with the way the Omex reads the signal. External power wouldnt be a problem as long it can accept 12v. Trigger signal would be a square waveform I imagine but what values I dont know that.

The current being switched would be tiny, but I will find out specifically.