--- Anand Dhuru <ardhuru@vsnl.com> wrote:

> How about a 38  khz signal, being sent as 1 ms pulses; a 3 pin IR detector
> =

> Anand

> From: "Richard Prosser" <rhprosser@gmail.com>
> =

> > Do they need to detect motorbikes / bicycles / golfcarts  etc..
>
Hmmm. Looks like it's either an IR sig, modulated @ 38-40kHz, to a reflector
and back or a magnetic sensor, Honeywell probly.
The reflector set up would work, I'd say, but needs to be aligned + I'm
thinking about battery capacity if you're flashing the light non stop all d=
ay.
The battery wouldn't have to be particularly small, however. =


The gizmo described in that Si-chip article used a hand wound sensor coil, =
so
not really practical. Basically, it was a metal detector cct like you go af=
ter
nuggets with.

So, OK, I have a few 3-pin IR rx/demodulators ... will do some expts, see h=
ow
it looks. Thanks for all the tips, guys.
Debbie =


PS: It's mainly cars they want to count. Bikes etc don't pay so not of
interest. I think motorbikes do but I'm guessing a big bike like a Harley or
top end BMW would probably have a (magnetic) signature like a car anyway.


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