CDI, accelerometer

[Webb]

One more "lurker" interested  :-) I've looked at a number of
designs, and they are all interesting.

I have a simple version that I designed on CAD, but never built.
I used a 555 astable, set to 1 mS,  with a counter that enabled
the 555 when reset by the pickup, and disabledit after 4 cycles.
The High voltage was another 555 astable, driving a 6.3 volt
filiment transformer backwards (with 12V oscillation swing) to
put out about 230 volts, which was then used to charge a
capacitor, and the 4x 1ms pulses fired an SCR - into a CD coil.

I figured if the thing hadn't fired after 4 tries, it wasn't
about to - and at the max rpm I was interested in, the 4th firing
was still looking at a dead cylinder, so no need to cut down the
number of sparks at high RPM.

555's are usually thought of as only for hobbyists, but there are
times when they produce very simple, elegant solutions. I'll dig
this one out if anyone wants...as I said, the design is untested
in practice, but it's simpler than the others I've seen, with
maybe $1 worth of parts (excluding pickups and coil)

marchildon at colba.net wrote:

> At 03:22 PM 8/29/97 GMT, you wrote:
> >On Fri, 29 Aug 1997 01:54:16 -0700 (PDT), "Robert D. McGhie"
> ><robert0 at jps.net> wrote:
> >
> >>At 04:41 PM 8/28/97 +1000, Stuart wrote:
> >
> >>>Sept. 97 Silicon Chip magazine has a multiple spark
> discharge CDI
> >>>unit as a project. The kit is about A$100 from Dick Smith.
> >
> >>Could you post or email Dick Smith's address or how to
> contact him?
> >
> >POST IT!!!, since there are at least TWO of us that are
> interested!!
> >Gotta be several others lurking (this fact derived from the
> "Law of Net
> >Lurking, which states that for every unlurked inquiry, there
> are at
> >least several others that wanted to know but were too
> >bashful/lazy/whatever to ask". 8)
> >
> >Garfield
> >
>
> Dito
>
> //
> marchildon at usa.net
> //
> // Alain
> Marchildon                                              //