Yea the paddles I was thinking of would be spring loaded and on a hinge so even if the bot hit hard and bounced back there's like 3 to 4 inch reach on the electrode paddles.

More like an end of train track bumper......that would work.

i cant do rovio but i could use the glyph thing and maybe use a infrared beacon so the bot know where to go that is invisible. can i tech him to like purple? because IR looks like white/purple through a camera? or maybe light the glyph with all IR leds so he seas it but is not annoying for me>? My house isnt too big, only kitchen and living room he could get to.

An IR emitter/detector pair would work for straight line of sight IE: your bot detects say 30% power left it would immediately do a 360 degree rotation to line up the detector to the emitter and then go forward, if it looses sight it would do another 360 to find it and again go forward until it hits the paddles.

Now keep in mind there is a lot left out as far as coding goes, like you could have the bot do a left turn, forward, right turn, forward to find the beam instead of 360 degree turn etc.

yeah i see what you mean but i really want auto charge capability. temporarely i can charge through the normal dc charge port manually in the back.

Why not something like the romba i uses. I believe the charger has an Ired transmitter on top, obviously sending some kind of signal the romba recognizes as a charger., and springy contacts. When the robot senses the batteries are low it starts searching for the charger.

The most useful would be to visually recognise a 110v outlet in the wall and plug into it eek