I have an application requiring very short range low speed telemetry.
Low cost is an overwhelmingly significant factor.
The application is to transfer an occasional on/off signal over a distance
of around 1 metre.
Transmitter and receiver orientation cannot be guaranteed. There may be
object(s) (possibly a person, metalwork etc) in the direct path although
there will not be solid metal blockage (OK - I'll tell - it's part of an an
exercise machine.).
For sufficient reasons the client wants a non contact path - wires (or other
media) are not acceptable.
I could roll my own (SAW stabilised oscillator, TRF receiver, ...) and might
even get below commercial cost but there must be some cheap short range
stuff out there. Everything I turn up seems to be slightly longer range and
cheaper would always be nice.
Did I mention low cost :-) ???

I'd be interested in hearing about the lowest cost units that people know
of.
Virtually anything that claims to be a telemetry link would work here!

I'll also look at Infra-red and Ultrasonics but RF seems most likely to be
the answer.


TIA

        Russell McMahon