There was a robot dog named I-Cybie that had a central chest IR sensor that would look for the IR signal from it’s charging station. THe IR LEDs on the charging station were somewhat directional, and the dog would periodically stop in approach, to see if it was still lined up on the charger from several feet away. Once within a 4-6" or so, the charger was shaped in such a way that the dog was guided into the 2 contacts on the charger at lower chest level. Worked pretty good, from what I heard.THe I-Cybie sensor was a simple modulated IR detector like a PNA4602. The charger IR LEDs were just small T1’s I think, with shielding to further narrow their beam.
Some Roombas also recharge, and I haven’t researched it, but also believe it’s IR to get near, then mechanical for the last bit to contact. Roombas have ther special omni-directional IR sensor, so not quite sure how that helps guide them in.
It’s a bit farfetched but You can get those wireless charging mats for things like phones and cameras, it might be a bit expensive but it would make it simpler than docking if it were possible. Just had a look, they sell some wireless power stuff here.
I was looking at your critter project and I may have a cheap wireless charger for the bot. It is an electric toothbrush charger. Wireless charging of (2)-NiCad batteries, and may charge (3) as the output voltage was not listed. Usually takes 3-4 hours to re-charge. Use the IR beacon to guide the bot to the "peg" on the charger and then the peg will take over the last 10mm. I remember paying about $15 USD for the toothbrush.
i thought of something like this. The docking station has two metal plates (the grey ones, one at the top and at the bottom). The bot has two metal thingys that come in contact with them (check the blue "contact" arrows). The one touching the top could be something like an antenna, like the ones you see on bumper cars. For the bottom you could use something like a caster, and connect it to gnd.
the Tuna idea have the advantage to allow very easy docking because do not require precise allignament AND leave the front of the robot free for other sensors (feelers)
on the other side voodoobot/gareth idea is more elegant because the robot have to manouver aproaching the plug…
2 feelers able to detect walls and receive current through terrarium plates
LEFT FEELER is easy to understand When left f. is free IN_L (digital in) is HI When left f. is pressed on a wall IN_L (digital in) LOW When left f. is in contact with negative Plate it join Outher and Inner GND
RIGHT FEELER When right f. is free ADC_R is 0v When right f. is pressed on a wall ADC_R is 1/3 Vcc When right f. is in contact with positive plate ADC_R is >1/2 Vcc (docking detected) and it joins charging plate with battery
