"Why rotate?" Consider a lighthouse - concentrate your radiated energy. "The beacons could be solar powered, (no mowing at night of course) with movable blinders to restrict their output to cover only the yard." Yet to see how this system allows you to navigate *inside* the yard in an effort to set up an efficient mowing pattern ... "You look around, and if you don't see the beacons, you're out of the yard." So - the sensor on the bot 'rotates' - looking for the beacons instead. This would work ... "If you see one, you're still out of the yard." Now I'm getting confused. You should always be seeing *all* your beacons (otherwise you can't navigate). IOW - this is a disallowed state. Also, I *did* mention a perimeter wire in conjuction with this approach ... "If you see two, then you can triangulate." I see how this relates. Again, a seeing eye or sensor that can resolve angular bearing. But - how do you know which beacon is *which* beacon? I was planning on a system design which used a method *not* entirely unknown in the free and enslaved worlds - the VOR system currently employed (but due to be phased out) for civilian aircraft navigation. A VOR 'range' station works on the principle of providing user equipment the ability to determine their 'angle' or bearing to the station - regardless of what that bearing may be. Fixes from two (or more) VOR stations fixes your positon. Additinally, each beacon \ would either 'rotote' at different rates (to distinguish them) or modulated at differing rates (i.e. 25 and 30 KHz). Appropriate S/W in the bot - and the 'bot can mow a raster-scan pattern in the lawn - thereby cutting all grass with little overlap and maximum efficiency of 'bot run-time. Jim ----- Original Message ----- From: "David VanHorn" To: Sent: Friday, August 31, 2001 12:24 PM Subject: Re: [EE]: - Botboard > At 11:57 AM 8/31/01 -0500, Jim wrote: > > "For mowing a lawn it may well be possible > > to have some IR Led marker posts at strategic > > points which the bot could sense." > > > >What if these IR LED markers were 'swept' at known > >intervals over the work area? > > > >What I mean is, what if they were 'rotated' in place and > >acted much like a VOR beacon. > > > >By taking the angular bearing from 2 (or more of these > >beacons) a very accurate position could be determined. > >Perhaps this in combination with a perimiter wire to mark > >the outer boundary? > > Why rotate? > The beacons could be solar powered, (no mowing at night of course) with > movable blinders to restrict their output to cover only the yard. > You look around, and if you don't see the beacons, you're out of the yard. > If you see one, you're still out of the yard. > If you see two, then you can triangulate. > > There are some nice solar powered lights made that I could see modifying > into mowbot beacons. > > Alternatively, the beacons could be set up the other way, so that as the > bot begins to get outside, it comes into view of the beacons, but I am more > comfortable with positive control. > > How would you deal with missing beacons due to kids or damage? > > One of these days, I want to launch on a mowbot. > I already have a B+D battery powered mower. > I have an irregular yard. The front is two rectangular sections, divided by > a concrete sidewalk, which is crossable, but only at certain points for a > mower. The back is one rectangular section, with two apple trees, and some > minor hazards. They are joined by a side which is about 4' wide. > > > -- > Dave's Engineering Page: http://www.dvanhorn.org > > I would have a link to http://www.findu.com/cgi-bin/find.cgi?KC6ETE-9 here > in my signature line, but due to the inability of sysadmins at TELOCITY to > differentiate a signature line from the text of an email, I am forbidden to > have it. > > -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics