Electronics Overview

Caribou uses a small family of custom PCBs, all designed in KiCad and developed in the open in engineering/electronics/pcbs/. The architecture builds on the Feather PDB and Quiver PCB designs.

Board Family

• CBC — Caribou Battery Connector PCB (6 per aircraft, one per motor arm) — interfaces an 18S smart battery with a motor arm: power switching, protection, voltage regulation, and dual CAN communication
• C90D — 90° Battery Adapter PCB (6 per aircraft) — mechanical/electrical adapter between the battery connector and the CBC assembly
• CMAIN — Caribou Main PCB (1 per aircraft) — central low-voltage avionics hub connecting all six arms to the flight controller

Per-Arm Power Architecture

Each of the six motor arms is an independent power unit:

Tattu 4.0 18S battery
        |
     [C90D]  90-degree adapter
        |
     [CBC]   fuse / precharge / kill / regulation / CAN
      |   \
      |    \-- isolated 12V + DroneCAN + signals --> harness --> CMAIN
      |
 [Hobbywing X15]  motor + ESC

There is no shared high-voltage bus between arms — each battery feeds its own propulsion unit through its own CBC. The CBC's galvanically isolated 12V output feeds the aircraft's low-voltage system via CMAIN, so a fault on the aircraft LV bus cannot back-feed into the battery power path.

CAN Topology

Two separate CAN domains:

• Battery CAN (per arm) — each CBC talks to its own Tattu 4.0 smart battery on a private CAN bus, reading pack telemetry (voltage, current, state of charge, temperatures)
• DroneCAN (aircraft-wide) — the CBCs, ESCs, and flight controller share the aircraft DroneCAN network, routed through CMAIN. Each CBC translates its battery's telemetry onto DroneCAN so the autopilot sees six standard battery monitors

Ground Domains

The electronics maintain strict ground-domain separation, labeled consistently across schematics and harnesses:

• GNDI — internal, non-isolated logic ground on each CBC (MCU, CAN controllers)
• GNDE — isolated external ground for the aircraft power distribution (12V system)

Deeper design detail — connector pinouts, power architecture, requirements, and review notes — lives with each board in the repository and in the pages linked above.