what's wrong with a low cost inductive timing light from some place like
Harbor Freight.
Mine cost like $ 19.95 and works just fine.
no need to reinvent the wheel.

a  NOID light ...there's a useful diagnostic tool .
if you want to make something, make one of those.
But those aren't very expensive either ..
they're are small and light, and very useful in a 'won't fire up'
situation with any EFI system.

On 6/18/2012 11:40 PM, tinker man wrote:
> Hello Volks,
>
> Since I don't have a ready-made timing light as well as would like to
> have a compact unit in the van for on the road problem solving on
> trips, I was thinking about making a compact one using a modern
> powerful LED (3-5W), since these leads and driver boards are available
> real cheap on the net (e.g. DEALEXTREME). What I need is a simple
> trigger circuit from the HT cable, hopefully by modifying a readily
> available LED driver board. has anyone already doen this and can save
> me the research time?
> Cheers.
>