Electronic Ignition Conversion?

on 04/02/2018, Dave Plowman (News) supposed :

I transferred my Piranha system, bought for a 4pot, over to my 6pot. It used a slotted disc/ photo-coupler which slid over the distributer cam, to time it. I was not able to buy a suitable slotted disc to fit the

6pot, so I after several attempts due to lack of proper tools, I managed to botch an accurate enough disc.

I agree about the much reduced plug wear, but why that should be I cannot even guess.

I think the problem is that 'daylight' contains many different wavelengths of light including the ones we can't see including IR and UV.

So, even if you went to a straight IR filtered sensor, daylight may still affect it?

A way often used to mask such effects is to encode the light source and then it will only react to that encoded light but I'm not sure if that could then impact the timing (it taking longer to qualify it was genuine data rather than daylight etc).

Would the simplest 'encoding', say a hf 50:50 duty cycle square wave be sufficient to differentiate between the optical chopper clearing the TX/RX module or the beams of sunlight flashing though the trees or a fence etc. ;-)

Maybe even if it did take some time to guarantee it was our encoded signal rather than noise, as long as it was a constant it could be included in the timing setting?

I upgraded the movement end stops on my 3D printer to optical switches (from micro switches) and printed long-armed shutters to amplify the movement and so make them quicker acting. They seem to work equally well in the light (inc sunlight) or the dark but I couldn't guarantee the trigger point was identical under all conditions.

On a more practical note, I think one of the disadvantages of converting an old points dizzy to optical is that you lose some of the damping you might get from the physical action of the points and hence (especially on a worn dizzy) see more timing scatter (the same applies to a mechanical advance etc).

Cheers, T i m

they are very small in my view to contain anything likely to cope with switching a coil I did wonder if they contained just a reed switch and small X7R type cap ;(

"For less demanding probably means not lengthy high revs

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