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some ideas
Posted: Mon Jul 11, 2011 10:57 pm
by CharlieM
Hello All,
Ok I have been doing some thinking on my ignition. What I think will work the best is to use a timer and measure the time the input is low. kinda like dwell. and from there I can work on what delay I need to get the spark curve I need. Does this seem like a accurate way to measure for engine speed?
Posted: Tue Jul 12, 2011 6:02 pm
by Senacharim
Isn't there a built-in location for connecting an RPM sensor?
I'd think that would be an easier way to gauge speed...
Posted: Tue Jul 12, 2011 9:43 pm
by CharlieM
Hi Senacharim,
This is for model airplane use. the only way I know of reading rpm is off the prop hub using a magnet and a hall sensor.
Posted: Tue Jul 12, 2011 9:47 pm
by Senacharim
Oh!
If your hall effect sensor changes state rapidly enough, then it should be fairly straightforward to wire it to one of the interrupt pins on the PIC.
You'll need a clock or some method of guesstimating when 1 second and/or 1 minute have passed...
IMHO that should work fine.
Posted: Tue Jul 12, 2011 9:50 pm
by Senacharim
Sry, should read a little more into your original reply.
I think so long as your sensor isn't too greatly modifying the electrical characteristics of the ignition then your proposed method should also work... of course you'll need to take steps to blunt the amperage of the ignition from ever reaching your PIC.
Posted: Tue Jul 12, 2011 11:03 pm
by CharlieM
Yesa I have the hardware done. I just to code up a pic.
Posted: Sat Jul 16, 2011 6:07 pm
by bitfogav
What exactly does the hardware consists of?
Posted: Sat Jul 16, 2011 6:53 pm
by CharlieM
The hardware consists of a pic,some resistors a npn transistor and two caps.