Boat PCB V3

D.R.E.A.M.S

Autonomous survey catamaran: CV-based obstacle avoidance, environmental sensing, and cellular telemetry to a web dashboard.

Website: https://ka1e27.github.io/dreams/ (the boat, the build log and weekly updates). Its source is in website/. Instagram: @dreams.boat.project.

Status: V3, starting from scratch

V3 is a ground-up rebuild on new hardware. The carrier PCB is designed and fully routed. None of the software has been written yet. This repo is the clean base it will be written on.

The V2 boat is archived, not deleted. The whole V2 stack is frozen at the tag v2-final: RP2040 firmware, the Pi 5 navigation and CV code, the dashboards, the cloud pipeline, and the V2 board with its docs.

Start with docs/v3/V3_DESIGN_BRIEF.md for the locked decisions, the current budget, part choices with their reasons, and the layout traps the first attempt hit.

The boards

Power on the V3 carrier (rev F): two 10S 10 Ah Li-ion packs in parallel make one 10S bus.

• Drive: the 10S bus straight to the VESCs, off-board; the carrier only senses its voltage.
• Electronics: 10S → 5 V buck → Pi and both Picos. An optional 4S backup on J18 keeps that 5 V side up while the 10S bus is off. A 15 V regulator (U15) feeds the stepper driver and the pod.
• Winch: 10S → P-FET kill → ESC.

Pack fusing is off-board. On the board, PTCs guard the pod feed (F1) and the LED and SBUS 5 V outputs (F2, F3).

Architecture

Raspberry Pi 5 ─ navigation, mission logic, CV, cloud link        Python (not yet written)
  │ UART on the GPIO header to Pico A, plus a reset line to each Pico
  ├─ Pico A (Pico 2) ─ control                                    C++ (not yet written)
  │    ├─ CAN via TJA1051T/3 ─► VESC ×2 (node IDs 1, 2) for drive, on the PIO (can2040)
  │    ├─ UART ─────────────► SBUS RC receiver
  │    ├─ PWM ──────────────► winch ESC, behind a fail-safe-OFF high-side P-FET kill
  │    ├─ STEP/DIR ─────────► A4988 radar-bar stepper
  │    └─ GPIO / ADC ───────► WS2812 status LED · hull leak L/R · 10S pack divider
  └─ Pico B (Pico 2) ─ sensors                                    C++ (not yet written)
       ├─ I²C via TCA9548A ─► SHT45 ×2, BNO085, ADXL375, BH1750, INA228 ×2
       └─ UART ─────────────► GPS (M10-25Q) · pod tether (RS-485)

• The Picos sit in sockets under the carrier, with a UART link between them. They replaced the Teensy 4.1 in rev E (2026-10-13).
• The Pi talks to Pico A over a UART on its GPIO header, and Pico B reaches the Pi through Pico A. So USB cables are optional: without them the Pi's USB ports stay free for cameras and the modem; with them, either Pico can be flashed or run its link over USB instead.
• The pod tether carries one RS-485 pair and 15 V; the pod makes its own 5 V.

Repo layout

Boat_PCB/Boat_PCB_V3/     KiCad 10 project: schematic and layout of the V3 carrier
Boat_PCB/Pod_PCB_V3/      the pod board (XIAO ESP32-S3 on the winch tether)
Boat_PCB/Boat_PCB_V3_1/   V3.1 starter carrier: Pi 5 + one Pico 2, an interim board
Boat_PCB/lib/             the dreams_v3 KiCad library all three boards share
Boat_PCB/CLAUDE.md        board baselines, layout constraints, ordering
docs/v3/                  design brief, planning record, BOM, V3.1 notes
website/                  the public site
CLAUDE.md                 working notes for Claude Code

Checking a board

Open the project in KiCad 10, or check it from the command line:

kicad-cli sch erc --severity-all Boat_PCB/Boat_PCB_V3/Boat_PCB_V3.kicad_sch
kicad-cli pcb drc --severity-all --schematic-parity Boat_PCB/Boat_PCB_V3/Boat_PCB_V3.kicad_pcb

Each board's current numbers, and the layout rules to keep, are in Boat_PCB/CLAUDE.md.

What changed from V2

V3 contradicts V2 on purpose. Don't try to reconcile the two. See docs/v3/README.md for the full table.

Sponsors

PCBWay sponsors the project's circuit boards.