I made the trigger wheel with nothing more than a compass, drill,
rat tail file and a pair of tin snips out of .032" thick Al. I drilled a
bunch of holes and filed out the connecting material. The same way
Charles Taylor made the Wright Brothers crankshaft :)

The hub I had lying around from an RX8 trigger wheel test.
That of course was made on a lathe. A DC motor spun the trigger
wheel. The up time on the scope is the dwell time. The plug
fires when the wave goes low.

This is a very simple and cheap ignition system as Chev V8
coils with built in FET switch can be had for $30 each. Four are
needed. Timing is fixed around 22 degrees BTDC.
Same as most AC engines.

Paul Lamar