yea, that's the same thing
what you posted is EXACTLY the opposite of what I was doing... BTW, you're a prick
It tends to work that way when someone says they want something but wont give the full specifics as to its intended purpose and usage. IF you went into a electronics engineering firms office (basically what you have here but with free consultation) and told any electronics engineer what you wanted in the same way you have told us they would probably all be pricks as well.
Your the one with this incredible "secret" about some more than likely off the shelf part or system that has probably been around for a very long time in one form or another that already does or could easily be modified to do what you want.
A good number of people here have strong skills in auto electronics and auto mechanics. But they are also the ones like me who have little interest in helping you at this point because of what we see as being pointless and quite childish secrecy issues.
The problem we have and know from experience is that just one single electronics device is not the whole and complete answer to any automotive problem. A vehicle is a complicated electrical and mechanical system that has many complex interacting components and variables that need to be accounted for.
We also know that very few control systems on a vehicle can be operated by just a simple on/off switching of a relay. Most everything is of proportional control of one form or another.
By explaining the full system you are trying to design they probably could and would be far more helpful. Unfortunately from the view point of most its apparent that you are hiding something.
Why and what for we dont know. But what we do know is so far your story seems to get more holes in it every time you post a vague referance to what you are doing and thats where our attitudes are coming from.
By the way a few of us here know exactly how to build your device and find it rather simple too! But well, you know.
(Its a secret.)