Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!think.com!mintaka!ai-lab!captain-crunch!klaus
From: klaus@captain-crunch.ai.mit.edu (Klaus B. Biggers)
Newsgroups: comp.robotics
Subject: Re: CALM (computer-aided lawn mowing)
Keywords: feasibility, beer
Message-ID: <16607@life.ai.mit.edu>
Date: 21 Jun 91 17:42:52 GMT
References: <1991Jun20.192334.24623@auto-trol.com> <20073@csli.Stanford.EDU>
Sender: news@ai.mit.edu
Distribution: na
Organization: MIT Artificial Intelligence Laboratory
Lines: 40

In article <20073@csli.Stanford.EDU> cphoenix@csli.Stanford.EDU (Chris Phoenix) writes:
>Another possibility:  Bury a wire under the yard, and make your machine follow
>the wire.  This is simplest--you don't even need a computer.  But it takes a 
>lot of wire for a big yard, and you have to worry about something breaking the
>wire.  (Of course, you have to worry about something removing the reflector,
>too.)  I don't know what kind of circuitry you need to make this work--I would
>guess an RF generator you hook up to the wire, two antennas on the machine,
>compare the signal strength from the antennas to decide where to turn.
>
>If anyone has any feedback on anything I've said, please tell me, either in
>e-mail or on the net.  Thanks!
>

I like that idea best... I saw an add the other day by a company
called invisible fence. You bury a wire around the perimeter of your
yard and then put a special collar on your dog. When the dog gets
close to the wire, his collar beeps, and if he continues on, it then
gives the dog a mild shock. It seems you could use this type of
approach to tell the mower to turn around but not completely. It may
be possible to just let the mower make a random pattern over your
yard.. It would eventually cover all of it unless it got into some
sort of limit cycle. You could probably increase the efficiency by
making the mower take a curved path or arc. You could also bury wires
around flower beds, swimming pools, etc.  and you could put some sort
of bumper on it to get it to turn around when it hits a tree. I've
seen automagic pool sweepers that work on this random traversal
principle and they seem to work quite well with respect to covering
the entire pool. You may want to add a grass level sensor to determine
if the grass you are passing over has already been cut and if so,
alter your path.

Then again you could get an expert system... a son or daughter...
they could even get you your beer out of the fridge and if they
refuse you could always dig out that old dog collar and activate
the fence again :). (just joking).


-klaus                                              klaus@.ced.utah.edu

_______________________________________________________________________________