I might put one on the Riding Lawn mower just for kicks.
I know they don't cost much on Ebay, but I'm looking for a thing to do!

 

I have several commercial ones in various equipment. I have AC-powered ones for my deep-well pump and generator. I have DC powered ones in airplanes and in a boat...

I am at a point in my life where it is easier to find $30 to buy one, than it would be to find hours to build one from scratch. If I was going to build one, I'd be looking at an Arduino with an LCD attached...

 

I use the Briggs & Stratton model on my boat motor. I can't imagine bothering to build one, but if I did, I would reverse engineer the approach used in that device. I think it's something like a simple count-up clock with an enable pin that responds to inductively sensing current in the plug wire. So the clock only advances when the plug is firing.

A 555 timer circuit can function as the missing pulse detector - no plug firing for 2 seconds, turn off the clock - but since you're going to need a good clock anyway, I imagine you'll want to use a microprocessor for all functions.

 

Many for ~$9 on eBay.

Ken

 

Thanks guys. I know about the Ebay offers ect.
I'm way too old and slow to do any Reverse-engineering.
I'll just not bother.
Thanks again....

 

Knowing when to make and when to buy is one type of wisdom. In this case, buying is the more logical choice.

There are many electronics projects that might interest you and be more fun and less challenging than this one.

 

I just got the Email saying "You won" an Hour meer from Ebay. I'm OK now.