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Subject: 
Re: Ball-less mice (was :Re: FW: Another DIY sensor)
Newsgroups: 
lugnet.robotics
Date: 
Thu, 30 Nov 2000 17:40:41 GMT
Original-From: 
John Barnes <BARNES@SENSORSsaynotospam.COM>
Viewed: 
1165 times
  
Jason wrote:

>Doing a little research, I found out that, when
>used with ps/2, mice are supplied 5 volts dc and have two data outputs,
for a total
>of 4 wires. I'm not sure how much power the rcx supplies, but optical
mice should
>be able to work with the rcx. The only problem is getting the rcx to
understand the
>inputs and what to do with them...

I was the one doing the experiment. But my investigation is not to use the
mouse as
is, but to use the parts, which I have done. There are two optical shaft
encouders per
mouse in the ball type. Each one can be built into a brick* with an LM393
to square
up the A and B channels to give outputs that the RCX can use, just as if it
were reading
from a Lego rotation sensor. I get 144 counts per rev, which is quite an
improvement
on 16 if you need increased precision. (You do have to be careful you don't
turn it too
fast otherwise the firmware skips/misses counts.)

(*The "brick" in my case is 2x4 x3 high, slightly taller than the Lego
rotation sensor
but not bad.)

I haven't managed to get my hands on one of those ball-less ones yet, but
someone
posted the url for the Agilent data sheet for the key part and I note that
it can run in
quadrature mode,  which means that it too can probably be interfaced
directly with
the RCX. If and when I get to try it, I'll let you know.

JB

ps: I am teaching myself "front page". When I get a bit better at it, I
plan on making
some of the sensor designs I have been working on more accessible via my
web page.
www.borg.com/~pinkmice. Of course, that means I'll need a digital camera to
take all
the pictures with, and with Christmas coming .. umm there's a plan.

So please be patient.



Message has 1 Reply:
  Re: Ball-less mice (was :Re: FW: Another DIY sensor)
 
Oh. I sort of figured that you took the stuff out of the mouse (i just went back and read all the messages ;), it just that I have an optical mouse and i wouldn't want to take it apart. if the rcx could read the outputs from the mouse directly, then (...) (24 years ago, 30-Nov-00, to lugnet.robotics)

Message is in Reply To:
  Re: Ball-less mice (was :Re: FW: Another DIY sensor)
 
(...) I can confirm this, at least for the US market; I just bought the Logitech optical wheel mouse, and it was $30 at Fry's in Campbell, California. (24 years ago, 28-Nov-00, to lugnet.robotics)

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