Re: Simple DRO new idea

Hi Group,
For those of you who want to play with a HALL effect
switch and split ring magnet, you can find these in the
12 volt fan of a computer supply. There is even a transistor
amp inside. Just disconect the field coil and run two wires
out the back of the fan. Every time the fan spins once the
output goes high to low or low to high. The signal is bounce
free.


Bob

--- In CAD_CAM_EDM_DRO@y..., "HighTech" <hightechsystems@h...> wrote:
> Scott
> I am working on a very simple dro using a special purpose Hall
effect sensor
> and a simple up down counter connected to a 8 digit led. It would
work as
> follows
> a linear magnet strip or a ring magnet with alternating north and
south
> magnet passes in
> front of the Hall effect sensor. This generates a pulse train to
the counter
> circuit.
> The sensor as has a direction output that is updated first before
the pulse
> so no lost steps.
> By using a timing belt and gearing the rotary motion of the ball
screw or
> lead screw can be
> multiplied or divided based on the number of pulses of the ring
magnet to
> equal an accurate count.
> I will be sharing what I find with the group as soon as I finish a
> proto-type. I am currently looking for a ring magnet if anyone may
know
> where to find any or have some let me know.
> Derek B.
>
>
> -----Original Message-----
> From: Scott Riddle [mailto:sariddle@l...]
> Sent: Sunday, September 02, 2001 9:40 AM
> To: CAD_CAM_EDM_DRO@y...
> Subject: [CAD_CAM_EDM_DRO] Simple DRO
>
>
> I just thought of this last night and I am sure some one else has
to or it
> is already out there but I would like to put a cheap DRO on my
Index Milling
> Machine and don't want to spend $600-1200 to do it. What I was
thinking of
> was a simple rotary encoder with a shaft of a special diameter and
to use a
> wire that is anchored on one end of the movable part of the slide
it would
> then be strung along the slide wrapped once around the shaft of the
rotary
> encoder and continue along the slide and the anchor at the other
end with a
> spring to keep good tension on the wire. The rotary encoder would be
> anchored to the stationary part of the slide assy. When the movable
part of
> the slide moves the wire would roll around the encoder shaft and
translate
> linear motion into rotary. A encoder with quadrature with 4,000
counts per
> rev and a shaft dia of .63662" would give 0.0005 linear travel per
encoder
> step. There would be a little work coming up with a small LCD
screen and a
> few buttons and a basic stamp program and controller to run it all.
>
> What do you guys think? Are there some other simple cheap DRO
options?
>
> Thanks
> Scott
>
> Scott Riddle
> sariddle@l...