Pages: [1]   Go Down
Author Topic: A Spark plug controlled from the Arduino - Review of guide  (Read 2661 times)
0 Members and 1 Guest are viewing this topic.
0
Offline Offline
Newbie
*
Karma: 0
Posts: 19
Arduino rocks
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Hi

I am using an Arduino, Mosfet and ignition coil to make a spark plug spark.
- I have put together this little guide for others, who might need to control spark plugs.
http://christian.liljedahl.dk/guides/arduino-spark-plug

The setup works fine for me, but my electronics skills are not at guru-level.

Do anyone foresee any problems in the current setup? - I don't want to have a guide that misleads people  smiley

Kind regards
Christian Liljedahl
Logged

Dubuque, Iowa, USA
Offline Offline
Edison Member
*
Karma: 45
Posts: 2469
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

The Arduino out to the gate of the mosfet needs a resistor (~220ohm). You need to limit the current being supplied by the pin as the maximum rating is 40ma and charging the gate on a mosfet can pull a bit more juice .. albeit for very short periods of time.

Good writeup. Interesting stuff.
Logged

Humboldt, CA
Offline Offline
Full Member
***
Karma: 2
Posts: 223
Arduino BBB
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Be aware that ignition coils will kick between 30 and 400 volts back out the - post, in the long term your MOSFET may suffer because of it.  A MOSFET rated for 500V or more is a good idea for long term life.
Resistor wise I'd use a ~125ohm, that nails 40ma on the nose.  If you aren't concerned about the lifespan of the Atmega chip you could use lower I suppose.

Other than that, I'd say you're set.
Logged

0
Offline Offline
Newbie
*
Karma: 0
Posts: 19
Arduino rocks
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Thanks for the advice! - I will test it out and update the circuits accordingly.

I did look at the circuit in my oscilloscope and noticed some pretty hefty voltage spikes.
- Probably a good idea to try to keep these down.

My high-voltage (tesla-freak) friend looked a bit concerned at my design too, so I will put in a few of his updates too.

I will submit an update when I have tested and written it. :-)

Kind regards
Christian Liljedahl
Logged

0
Offline Offline
Full Member
***
Karma: 1
Posts: 140
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Hi,
there are ready-to-us chips on the market to drive a ignition coil.

Take a look at this: VB921. I've seen that on Ebay recently. See
Logged

Offline Offline
Newbie
*
Karma: 0
Posts: 13
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

interesting project, I will have to try it.  One question on the Arduino Uno and Mega would they have the speed to keep up with a cars ignition/fuel system timing?
Logged

0
Offline Offline
Full Member
***
Karma: 1
Posts: 140
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Speed is strongly depending on code. But having a 2stroke engine having currently a fixed ignition retard everything is better than that.  A delay of 8microseconds at 8000RPM would mean a 0,4°retard, which is acceptable to me...there is no such accuracy in calibrating the engine with defined air temperature and engine temperature...

Firing a multicylinder 4-stroke engine is much more challenging and I do not have the software knowledg to do so...
Logged

Pages: [1]   Go Up
Jump to: