>> i don't think that any of us (with lawns) haven't thought of this project. i
>> see they have a link to the 2x compass. i read the specs and didn't feel
>> that this device was accurate enough for a guidance system. counting ticks
>> on the wheel revolutions won't work either because the ground is not flat. i
>> saw a robot show on tv where they used dual gps receivers about the size of
>> a pack of cigeretts. does anyone know who makes devices like this. or how
>> would you send a robot 200 feet (70 meters) down a property line without
>> mowing over your neighbors flower garden?

Surely this is an ideal project for ultrasonic ranging:

Four ping-ing transponders (well, three, but four for reliability) at the
corners of your lawn triggered by low-power radio from the mower-mounted
controller will give you accurate distances, hence position. You need to
walk the mower (or just the controller) around the area to be mowed,
logging coordinates as you go, and then let it fill in the bit in the
middle. The ultra-sonics will probably keep the moles away. too. <G>.

I know this kind of technique has been used on automatic follow-spot
systems for stage use. It had a PC as the 'smarts' but a PIC might do.

Incidentally, on the subject of splitting this list: I believe if you try
and separate out the threads into newbie stuff, advanced stuff, OT stuff
etc. you'll kill the reasons the list works well. I'm just as interested to
hear about ideas/problems/solutions in the electronics you find around a
PIC as in the PIC itself. Yes, it does take a while to trawl through all
the messages - but the advantage of having such an active list is that if
you post a query you can bet on a replies within 12 hours. I think the
occasional rambling thread (Canadian accents comes to mind?!) is a small
price to pay.

Alec

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