Tom Handley wrote:
>
>    Roman, all I have is a Kodak webcam that does 640x480 right now but I
> definitely want to put pics and other info on my web site.

What's wrong with that? :o)


>    I was concerned about speed control and I spent a lot of time looking
> into a tach. There just isn't enough room in the gear box around the motor
> shaft and the first gear. It's a worm gear on the motor shaft driving a
> second gear, driving a third which drives the output shaft gear. I was able
> to drill four holes in the third gear and fit a matched IR pair in the
> housing but it's still not really useful for a tach at short distances. I
> can still add gears to the other end of the output shaft to gear-up and get
> a decent pulse rate though it's very inefficient. Right now I get one pulse
> for around every 5/8" traveled so that's good enough for distance
> measurements.

As a suggestion, I normally use reflective IR sensor
pairs (pigsnouts) which are about 4mm square. If you
can get one close to a cog (closer than 5mm) and
put some black/white paint stripes etc on the cog face
it will work fine. This is what most of the newer
VCRs do, it's smaller and cheaper and more convenient
than an opto-interrupter.

The Sharp RHPX 0181 GEZZ is about $3 US in singles
and is tiny! Any TV repairer should have them in
stock or could order them if you want some. I could
get you a couple if you like.

>I eventually plan on adding a Vector 2x electronic compass.
> Given the identical Mabuchi motors, the quality of the gearboxes, 336:1 gear
> ratio, regulated H-Bridge supply, and matched MOS/HEXFETs, it's really not
> surprising that it tracks so well.

Obviously your motor drivers are good but it
mainly comes down to the quality control of the
motors, which is obviously good! :o)


> I thought the rear castor would give me `fits' when backing up but it
> works great. It's a small castor with ball bearings available for around $3
> from any hardware store. One big factor is the front wheels which came from
> the R/C car I was hacking. They are around 3" in diameter with 1/8" knobs
> and 1.5" wide.
>
>    As far as purpose, it's mainly an R&D platform but I'd also like to
> freak-out the cat. The problem is that I would have to detonate some C4 near
> the cat to get it's attention ;-)

Cool! You could get it to chase the cat and make
electric shocks?? ;o)

-Roman

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