Turbo speed sensor - ferrite in comp wheel ?

[Mike (Perth, Western Australia)]

At 04:37 PM 9/03/2000 +0200, Nic van der Walt <nvdw at cellpt.co.za> wrote:

>> I really would like to do a turbo speed sensor - so far no reply from
>> the emails I've sent out to distributors - not even a "we don't do it" :(
>
>What could work for a turbo speed sensor is strapping a microphone to it
>and listening to the frequency it screams at. A wideband knock sensor would 
>work well. On my bike I can clearly hear the turbo sweeping through the 
>frequencies as it speeds up.

mmm Hadn't thought of that - I suppose a cal check with an optical tacho
would be the thing, since I've noticed the note changes with the length
of inlet pipe and even type of air filter...

More I think about it - I'll go for a very small hole in the edge of the
comp wheel - keep the aluminium swarf, weigh up a small ferrite bead and
glue/wedge/solder this in to the hole. Hopefully the 0.05g difference
won't radically upset my comp balance. With that setup and a fast
reluctance pickup I should be able to get precise indication of speed.
Will be an interesting exercise.

Any comments on the best means to attach a ferrite bead into the edge
of the comp wheel and not have it fall out at 150K rpm ?

<groan>

?



Rgds ~`:o)

Mike Massen         Trading as "Network Power Systems" and "Network Computers"
Perth, Western Australia  Ph +61 8 9444 8961  Fx +618 9264 8229 (fax -> email)
Products/Personal/Client web area at http://www.wantree.com.au/~erazmus
 (Current pics - trip to Malaysia to install equipment in jungle power site)

Some say there is no magic but, all things begin with thought then it becomes
academic, then some poor slob works out a practical way to implement all that
theory, this is called Engineering - for most people another form of magic.

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