How to Detect our Car's Engine is Running or Not?

[Mechatrommer]

How often do you try to start the car when it's already running? The way I get around the problem is by having a car with an incredibly noisy exhaust. You should be able to have a noisier sports exhaust fitted fairly quickly. As an added bonus, your car will impress more people and set off car alarms.

i dont know... maybe like 2-4 per year accidental re-ignition. large exotic exhaust? yea! i'll get another 3 extra bonuses... 1st i'll be going nuts each time i drive due to noise, 2nd i'll be less alert to surrounding traffic, and 3rd is an impaired hearing ability just after come out of car after driving. drove my lil brother's car, will avoid it as much as i can. FYI, he is a car sound system/box assembler/tuner and own a car accessories shop, but... he knows shit about electronics

and the kicker is, i usually noticed that when my wife is going to drive, i'm sitting right next... she got a habit to keep the key in ignite position longer than the engine ever need to be running, sure the high pitched sound will not be much noticable as continuation from engine cranking, but i believe, with such protection circuit, will save the starter and engine life in the long run due to this habit.

so the circuit i'm designing is not just to avoid accidental re-ignition, but also set the optimum time needed for the starter to energize/crank the engine, ie cut the starter just after the engine is running normally.

[joelby]

Well, you could just explain to your wife why she doesn't need to crank it for so long. Maybe she'll be less annoyed by that than you spending weeks in the shed on an engineering solution and dismantling your car?

Anyway, if you look at http://www.podecoet.org/ under "Enginering Project (Remote Engine Start)", you'll find some information about how an automatic engine starter was made. Sounds like it could be adapted for your use.

[Mechatrommer]

well... the guy use the tachometer. thanx for the link