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Topic: Messuring signals of a cable with induction (Read 635 times) previous topic - next topic

4things

I'm planning to messure the frequency of the ignition signal from my pocket bike. I was planning to use a simple antenna in combination with an arduino analog port to messure the inducted signal. Should i use a digital port instead of the analog ones. The program should be the same as the Code to use to analyse a reed contact

Thank you in advance

4things

elandd2011

Need more info
Your idea is not new,you use a simple cable as antenna to get the signal 
but you have to take care about signal levels don't go very high and
keep it between 0 and 5 volts , so have to use a limiter.
The limiter can be very simple or complex, do some googling
and you will fine many examples

Bobnova

Personally I'd be more inclined to tap the (or a) coil negative/ground wire via an optoisolator.
It'd trigger every time the coil is fired, but is safely insulated by the optoisolator.

The negative coil post itself could be used with a diode to keep the 12v out, but the coil firing can produce as much as 400v on the negative post.  The optoisolator cleans that up and will happily ground a wire you've pulled up with the arduino.
Doing it that way you get nice clean triggers without having to worry about your induction antenna giving you >5v, or a spark leaking through the plug wire into the antenna and giving your arduino 70kv to think about.

The optoisolator setup is what the Megasquirt DIY MCU based EFI computer uses, or at least used for the first couple versions.

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