Why bother making your own sensors. Go to scrapyard and you will find
plenty of engines that have them.
Cost of such a sensor lies around 5-6$ in volume production, they are
very simple in design and work fine even when there is metal power
accumulating on the magnet.
If you want TDC detection check for more recent engines. Take the sensor
and also the code wheel. It will have slots with different sizes.
TDC detection enables firing at the right moment.

You need signal conditioning electronics as well.Usually it is
integrated in ECU or can be separate module, in combination with the
code that finds you TDC.
Check page 14 of http://www.gotechefi.com/images/gotechrotary.pdf which
might be of help to you.


Randolph

Thanks for the tips Randolph. I'll add the GoTech to our list
of off the shelf proprietary  ECU's. A bit over kill for our use as
Lambda sensors don't work for long with high lead aviation fuel.

We are designing our own code wheels and super simple non computer
systems.

http://www.rotaryeng.net/simple-cheap-555.html


Paul Lamar