On Fri, 02 May 2014 10:38:13 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Larry Jaques fired this volley in
:

LJ's 2-cents: Optical seems the best route. If it's a dirty enviro,
shield it, wot?


Still... why not a vibrational pickup? Then there's _nothing_ to get
dirty, no imbalancing of the engine, and no 'attachments'. Just mount the
pickup _near_ the motor mounts and be done with it.

They've got them in teesy sizes that will handle up to a couple of hundred
KHz, can consume NO power (some active ones will pull a couple of mA.)

Vibe tach? Nevahoiduvit. Are they available?

--
If government were a product,
selling it would be illegal.
--P.J. O'Rourke