I just found out the 5 volt output comes frome the 7805 in the schema!!
This feeds the chip/IC and the hall sensor.

When I have some spare time I am going to built one (next year or so) because I like it a lot, it's simple and I believe it works.

Blimey, that's certainly interesting!

The bits I think I understand are: the 16F168 is a 'Pic' microchip - ie: one that is essentially 'blank' and has to be programmed to do what you want. It's like a very basic computer RAM chip - basically a memory chip that you can feed lines of instructions into and it will then hold this info and carry out the given task.

The 5Volts comes the rectangular 7805 block in the top right hand corner. That is a little three-wire component which is a voltage regulator. You feed anything from, ooh, 8 to 18 volts (something like that) into it and a steady 5V comes out t'other end. This is needed because the Pic chip needs a regulated 5V to work.

The stuff at the bottom left hand side is - I think - a 'Hall-effect' switch (well, it does have 'HALL' written on it!). A hall-effect switch responds to magnetic pulses, and these are commonly used in contactless ignition systems such as 123 and Lumenition. So, I guess that'll be the sensor and you'd need to fit a suitable magnet (or two?) on the cam.

Finally, there's the big 'Diode Integree' at the top left - that is a 'Power Transistor' of some type. It is there to respond to the output from the Pic chip and then switch the 4 amps or so that the coil needs to function. Chips are delicate beasts with tiny outputs; if you tried to connect it to the coil directly, it would go kaput.

The 'Bobine' is the coil!

So, once built, someone would need to program the Pic chip with instructions on what to do. I guess what you'd want it to do is to respond to varying speeds with different dwell angles and such like. There's a 4-pole switch in the bottom left hand corner - I don't know what these do, but I guess it would 'tweak' the action of the chip to cope with different conditions - perhaps slightly advancing or retarding the ignition or something?

So, it's a completely contactless leccy ignition system probably the equivalent of 123 or Lumen. All it needs is for someone to build it...


(And I see that lpgo is the guy to build it!)

Blimey. I went cross eyed at all that technical stuff. I'm running 123. It's been fine for years, but has done nothing for my fuel economy. Can I tell the difference between 123 and points when driving? No, I can't. But then i can't tell one type of spark plug from another. If it starts, and runs then all is good in my book.

Look at the the website. When you load the .exe file you can make your own ignition curve, dwell and rev-limiter and the you can save it as a .hex file which you can load into the IC using a "IC loading device".

devils advocate I think you know more about it then me (electronics) can you built it first

I think on balance I might go for the 123 jobbie, seems a lot less messing about even if I cant afford it at the moment... better start saving!

Don't forget to store all the 'redundant' parts in the boot.

There's been more than one 2CV driver I've known who regretted not having the fallback option available when 'fit & forget' didn't quite work out as planned...

ken.

It's not just me then!

Ken and I had talked/joked about doing a "blind test" at one of the events, to see if anyone could spot which cars were on points and which were on 123 or the like.

It all comes down to "I want the car to start, but I don't want to invest a bit of time and knuckle skin to do so, so ill deploy the 2"x 3" bit of plastic"

Sean

Very interesting stuff! I think I know where I'd be able to get my hands on a PIC programmer as well..! Interesting that the older version of the circuit had a capacitor across the transistor, whereas the newer one doesn't seem to. Or is that just due to the different transistor? My French is awful - was there a link on the site to any photos of how they've installed it all?

To be fair though there are sound reasons to ditch the points and go electronic besides laziness,

On a 123 the points box and advance retard springs are removed entirely. The ignition is triggered by 2 magnets placed over the pins for the bob weight springs and the ignition is triggered by a Hall effect sensor.

The advance curve as well as the dwell angle are programmed into the ignition unit and therefore gives far superior control over advance and dwell parameters than you can achieve with mechanical points.