Newsgroups: comp.robotics
Path: brunix!news.Brown.EDU!qt.cs.utexas.edu!cs.utexas.edu!uwm.edu!linac!att!cbnewsk!nastasi
From: nastasi@cbnewsk.cb.att.com (joseph.l.nastasi)
Subject: Re: Run Rabbit...Run. Cat detectors.
Organization: AT&T
Date: Tue, 23 Feb 1993 13:46:55 GMT
Message-ID: <1993Feb23.134655.12408@cbnewsk.cb.att.com>
References: <1mbht6INN2s9@clover.csv.warwick.ac.uk>
Lines: 68

In article <1mbht6INN2s9@clover.csv.warwick.ac.uk>, esrbu@csv.warwick.ac.uk (Mr I M Hunter) writes:

>         I wish to build a small (tennis ball sized) mobile robot that has
> a self-preservation instinct when faced with my cat. That is, it runs away
> from it.

Oh, I LOVE this idea!

I have two cats myself and after many years have decided to build a
small pet-like robot.  It's going to be a bit more sophisticated
than your plans, but the same idea: hang around and react to your
environment.


> The thing is how does it detect where the cat is and whether it
> has pounced upon my poor, doomed robot. I was thinking of attatching an
> infra-red emitter upon the cats head


I saw the post about IR movement sensors, but that will definately
blow your budget and an IR bonnet on yer kitty's head will tick 'em
off, for sure.

Starting with the simple problem, how about a dome (or wide cone)
over the robot that is pivoted in the center.  Two or four micros switches
arranged (oops, I forgot this things size)...rewind....zzzzzz...
How about having the dome supported by one micro switch (ascii graphics
time):

                   xxxx
                 x /    x         micro swtich lever
               x  ......  x       micro switch
             x    ......    x
            x                x
           x                  x
          xxxxxxxxxxxxxxxxxxxxxx
                    x    x
                     x  x         very bumpy wheels
                      xx


You'll have to make this thing sturdy enough to handle your particular
feline's size.  Some micro switches are sturdier than others.

> There needs to be a number of these receptors so that the
> robot detect the cat at any time.

With such a small size it would be difficult to use sonar because,
as with the IR sensor idea, it would require either multiple sensors
or a revolving one.  If I were doing this, I would leave the detection
to a simple "there's something on me!"  and concentrate on attracting
Pluto's attention.  There are plenty of noisey chips around and
piezo transducers are cheap.  BTW, what sort of brains are you
going to use.  Logic stuff or a cheap micro?

If you are using a micro, you can be very clever about getting away and
goading the cat...

I apologize for the length of this...Please feel free to contact me
via email for an ongoing dialog on this.  I'm very interested in
small "hobby" type robotics.

>                         All comments welcomed, Iain

Joe Nastasi
AT&T, Middletown, NJ
(908) 957-6365
nastasi@mtuxo.att.com
