protecting arduino output from ignition coil EMF

I want to use one of my Arduino output to make one of my motorcycle ignition sparks to misfire. From what I have read so far ignition coils are power supplied with 12 volt and when ground is disconnected the magnetic field creates high voltage on secondary coil and creates the spark.I want to drive a ground from an output of my Arduino in parallel with ignition coil ground so when I keep it grounded to misfire.I guess that the PWM that drives the ignition coil has already a protection.Can anyone help me with the circuit I have to build for my Arduino output.Thank's in advance

How fast do you need the action to be? What are you doing? Is this for RPM limit?

terryking228:
How fast do you need the action to be? What are you doing? Is this for RPM limit?

it’s for a traction control.misfire one of four cylinders when rear wheel spins faster than the front.I attach a diagram of how I want to make it work but I need to protect my Arduino and not burn anything that already driving ignition coil.Thank’s

A BC547 is a < 100mA small signal transistor.
Your ignition coil could draw a lot more than that.
Use a transistor that can handle the coil current.

To protect the transistor from back-EMF from the coil, use a diode across the coil.
So between collector and +12volt (cathode to 12volt).

This logic level mosfet circuit could work.


Leo…

Wawa:
A BC547 is a < 100mA small signal transistor.
Your ignition coil could draw a lot more than that.
Use a transistor that can handle the coil current.

To protect the transistor from back-EMF from the coil, use a diode across the coil.
So between collector and +12volt (cathode to 12volt).

This logic level mosfet circuit could work.
http://www.gammon.com.au/images/MOSFET_low_side_driver.png
Leo…

Thank’s for the answer.does this circuit make any affect on the factrory ignition coil circuit that is controlling already the coil.I don’t now if there is already a diode across the positive and negative of the coil at the controlling circuit for its protection.

nixtas:
Thank's for the answer.does this circuit make any affect on the factrory ignition coil circuit that is controlling already the coil.I don't now if there is already a diode across the positive and negative of the coil at the controlling circuit for its protection.

Don't know about that ignition circuit, but it could be.
In that case, I would use a small automotive relay.
Leo..

Wawa:
Don't know about that ignition circuit, but it could be.
In that case, I would use a small automotive relay.
Leo..

that was my first thought but i need minimum 4ms time so a relay can't switch that fast.

Why need it be so fast? after all 10mS is only 1 rev at 6000rpm...

Allan

allanhurst:
Why need it be so fast? after all 10mS is only 1 rev at 6000rpm...

Allan

some motorcycles revs up to 16000rpm