The dock: IR homing, spring contacts, no Qi
Bobby needs to find home and plug himself in. The plan is a rev-2 dock with a 38 kHz IR beacon, a mechanical V-funnel, and spring charge contacts — the Roomba playbook, because it works.
Triangulating the beacon
Three IR receiver modules sit in a left/center/right array on the front chassis face, the outer two toed out ~25° with little sun hoods. By comparing signal strength across the three, the spine steers the droid onto the beacon like a bloodhound. The same receivers can pick up any 38 kHz source — a TV remote can drive the droid, and a beacon on a keychain enables follow-me mode.
Cliff sensors pull double duty
Two downward-facing IR reflective modules under the front chassis watch for stairs and drop-offs: lose reflection while moving forward and the spine halts, backs up, and reports to the brain — which cannot override it. Bonus: pointed down, they're also line followers. Black tape on the floor becomes a navigation rail, for free.
DOCK DECISIONS
| Homing | 3× 38 kHz IR receivers, L/C/R array, ~25° toe-out |
| Charging | Spring contacts only — wireless (Qi) scrapped: slower, hotter, alignment-fussy |
| Charger | Proper 3S balance charger lives in the dock (rev 2) |
| V1 provision | Flat belly-pan area reserved for future charge pads |
Five IR-related GPIOs are reserved on the spine: three for homing, two for cliffs. The dock itself waits for rev 2 — v1 just needs to not paint us into a corner.
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