Re: mouse encoder

At 01:12 22/08/2001 +0000, you wrote:

>Nice work! Are you going to sell these? I'm curious about the sensor
>you used, and the circuitry, a PIC? Perhaps you'd share them with us
>(if you're not planing to sell them!)?

Alan -

Thanks.

I plan to sell the meter in kit form as an accompaniment to an article in
Model Engineers' Workshop, so the schematic will be published in the
article. The kit will include a pre-programmed PIC.

The circuit is designed for use with two alternative sensors - one is a
reflective IR sensor, good for about 500 pulses per second, the other is a
slotted IR sensor, good for much higher pulse rates.

The meter can handle 1, 6 or 60 pulses per rev (i.e., 1, 6 or 60 slots in
the sensor disc, or black/white marks on a shaft). I have tested the meter
with the slotted sensor and the 60-slot disc up to 14,000 RPM (the max I
can get out of my Taig mill/Sherline motor combination); with a 1-slot disc
this would make the meter capable of reading up to 840,000 RPM. However, I
believe that the sensor/meter combination is capable of handling higher
pulse rates - I just haven't yet pushed it to the limit. The sampling
period is 1 second, so a 60-slot disc gives measurements down to 1 RPM.

Regards,
Tony