Sensing Output From Spark Plug Cable Of Petrol Engine - Electronic Circuits Projects Diagrams Free

Achike · 9th April 2008, 10:35 AM

How can I sense induced voltage by wrapping a wire around the spark plug cable of a petrol engine. I have a a car alarm system that can remotely start my car. It came with a device that has a wire that you wrap around the spark plug cable to tell the electronics that the car has started. This system is sealed up by the manufacturer so I can't access the cct. I need an output that I can amplify to drive a 12V relay. Anyone with an idea? Thanks

RODALCO · 9th April 2008, 11:47 AM

A couple of turns of 1 mm² wire around one of the sparkplug leads will work fine.
Leave one end open and the other end goes to your BC547.
Bring that to the base of a BC 547. fit a base resistor 47k. and a protection diode + resistor to negative to protect your base from overvoltage.
A bit of trial and error may be needed, see what works best.
Than amplify signal to whatever circuit you want to drive.

I used it to drive a LED and a pulsecounter in my old Ford Falcon.

Achike · 9th April 2008, 12:47 PM

Thanks, I'll try that now and keep you posted

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9th April 2008, 10:35 AM	(permalink)
Achike	Sensing Output From Spark Plug Cable Of Petrol Engine How can I sense induced voltage by wrapping a wire around the spark plug cable of a petrol engine. I have a a car alarm system that can remotely start my car. It came with a device that has a wire that you wrap around the spark plug cable to tell the electronics that the car has started. This system is sealed up by the manufacturer so I can't access the cct. I need an output that I can amplify to drive a 12V relay. Anyone with an idea? Thanks

9th April 2008, 11:47 AM	(permalink)
RODALCO	A couple of turns of 1 mm² wire around one of the sparkplug leads will work fine. Leave one end open and the other end goes to your BC547. Bring that to the base of a BC 547. fit a base resistor 47k. and a protection diode + resistor to negative to protect your base from overvoltage. A bit of trial and error may be needed, see what works best. Than amplify signal to whatever circuit you want to drive. I used it to drive a LED and a pulsecounter in my old Ford Falcon. __________________ There are more ways to get to Rome. Electricity, Electric clocks, Meters and Trains are great.

9th April 2008, 12:47 PM	(permalink)
Achike	Thanks, I'll try that now and keep you posted