Project Caribou - June 2026 Progress Report

General
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Project Caribou — June 2026 Progress Report

1. Executive Summary

June turned May’s design work into ordered hardware. All three Caribou PCBs — CBC_PCB, CMAIN_PCB, and C90D_PCB — were finalized, reviewed, and sent to manufacturing by month end. The CMAIN_PCB went from finished schematics to a fully routed, reviewed, and ordered board within the month.

In parallel, mechanical integration accelerated: the CBC enclosure was designed and successfully test-printed, the CMAIN enclosure design was completed, the sheet-metal battery mounting structure was ordered and installation on the airframe began, and dual F9P GPS placement was added to the frame. Caribou Hub reached a deployable state on the software side.

July is the final month of Caribou Phase 1. With PCBs arriving in early July, the focus shifts entirely to PT1 assembly, ground testing, and the Phase 1 hover flight.

Top June results:

  • All PCBs ordered: 10× assembled CBC_PCB, 2× assembled CMAIN_PCB, and 20× unassembled C90D_PCB were ordered at the end of June (~10 day manufacturing lead time).
  • CMAIN_PCB completed: Schematics finished, board fully routed (ERC 0 errors / DRC clean of blocking items), silkscreen pinouts and rounded tracks added, all parts pre-ordered, and prototype ordering outputs generated. Includes a new Emergency_cutoff schematic sheet and a Raspberry Pi Compute Module + adapter-board direction.
  • CBC_PCB review closed out: Erick completed his review (power regulators, kill-switch/latching circuitry), an external freelancer performed an additional review with improvements, and Julius fixed routing/component issues (capacitor voltage rating, isolated DC-DC MOSFET selection) before ordering.
  • C90D_PCB v1.1 merged: The 90-degree battery adapter PCB designed in May was integrated into GitHub and included in the June order.
  • Enclosures progressing: KBM’s CBC enclosure was test-printed with good shell, lid fit, and connector-output results. CMAIN enclosure design started, including HM30 air-unit integration with Quiver-style screw-in antennas and a two-stage damping concept (enclosure-to-frame plus PCB-to-enclosure).
  • Mechanical integration started on the airframe: Old battery brackets removed and paint touched up, sheet-metal battery mounting brackets ordered (stainless holders for PT1), installation begun, F9P GPS placement added to CAD, and foldable beam connectors sourced (6 pieces ordered).
  • Caribou Hub deployable: Basic development of Caribou Hub and the Caribou System Unit is complete, with easy deployment via package release downloads and setup executables. Remaining work is testing and usage-based feedback once hardware catches up.

2. Team

June core contributors:

Contributor Role June allocation
Julius Project lead 30 h/week
KBM CAD / PCB 20 h/week
Alex Avionics / Caribou Hub 15 h/week
Erick Electronics review / support 10 h/week

Additionally, an external freelancer was hired for an independent review and improvements on the CBC_PCB (see Budget).

3. Progress

CMAIN_PCB — from schematic to ordered board

The Caribou main PCB was June’s central workstream. At the start of the month the schematics were being finished; by June 16 the board was fully routed with no DRC faults, and by June 29 it had silkscreen pinouts, rounded tracks, and final ERC/DRC checks, and moved to prototype ordering.

Key characteristics:

  • Quiver-style central electronics concept: many waterproof vertical connectors, voltage regulators, and battery/ESC interfaces on a ~210 × 220 mm board.
  • Redundant power architecture: 12 V from the six batteries combined into three redundant 12 V sources (each from two batteries), feeding three separate 5 V circuits — two for flight-controller redundancy, one spare for sensors/peripherals.
  • New Emergency_cutoff schematic sheet.
  • Raspberry Pi direction changed to a Compute Module with adapter board mounted into the main header, saving side space and improving future ventilation/heatsinking options.
  • Netclass-driven track widths/via sizes applied across 539 named nets; BOM audit against the JLCPCB parts export confirmed 255 references match both ways, with value fields cleaned up (voltage ratings added) for ordering.
  • All CMAIN parts in stock at ordering except the LTC4370 ideal-diode controller, which Julius will hand-solder.

Erick reviewed the CMAIN GitHub state before ordering.

Relevant work: issues #8, #34, #46, #48 and PRs #44, #45, #49.

DFM_JLC_CMAIN
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CBC_PCB — review, fixes, and order

The battery connector PCB moved from “needs review” to ordered:

  • Erick completed his review, working through the power-regulator section and the kill-switch/latching/trigger circuitry. The main clarification was that the U10 MOSFET switch is normally closed and the 12 V trigger signal opens it; the latch holds state through ESP32 reboots and startup reset defines a safe off state. Documentation notes were added to make this behavior explicit.
  • An external freelancer performed an independent review of the CBC_PCB and delivered improvements.
  • Julius fixed routing details and component issues found during review: a capacitor with the wrong voltage rating and two MOSFETs around the isolated DC-DC converter replaced with more appropriate fast-switching parts.
  • Netclass/DRC infrastructure was set up for the 2 oz copper, 6-layer stackup
  • The final ordered version was integrated into GitHub just after month end (PR #51), following the same pattern as May’s C90D work.

Order: 10 assembled boards (assembly chosen because hand-soldering ~6 needed boards would be very time-consuming). Rough cost for the 10 boards including pre-ordered parts: ~EUR 1,500, with the bare heavy-copper PCBs at ~EUR 372 before assembly/components.

Relevant work: issues #6, #31, #33, #47 and PRs #32, #42, #51.

DFM_JLC_CBC
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C90D_PCB

The 90-degree battery adapter PCB designed in May was merged into GitHub at the start of June (v1.1 plus manufacturing STEP) and included in the June order: 20 unassembled pieces, since the price difference between 5 and 20 was small.

Relevant work: issue #19 and PR #32.

Enclosures and vibration damping

  • CBC enclosure: KBM designed the enclosure (dust protection rather than full waterproofing for PT1) and Julius test-printed it in late June. Shell, lid fit, gaps, and connector output area all look good; validation with real PCBs and screw inserts follows once boards arrive.
  • CMAIN enclosure: Design started from the Fusion assembly, reusing the Quiver-compatible mounting-hole pattern. It integrates the HM30 air unit with Quiver-style left/right screw-in antennas, keeps ~4.3–4.4 mm flight-controller-to-lid clearance, and mounts around the center beam. First design iteration is ready for a test print.
  • Damping: PT1 uses a two-stage stack — rubber damping between enclosure and frame plus softer damping between PCB and enclosure, similar to Quiver. A standalone/floating flight-controller board was discussed and deferred to a later version.

Relevant work: issues #26, #36, #37, #41.

Airframe, battery mounting, and peripherals

  • Old battery mounting brackets were removed and paint touched up; new sheet-metal battery mounting brackets were ordered and attachment to the drone began. Stainless-steel battery holders were chosen for PT1 (heavier than aluminum, but safer for the first prototype).
  • Two F9P GPS units were placed front/back in CAD for GNSS heading, with the Matek compass kept as fallback (Matek GPS likely disabled). A 3D-printed adapter for frame mounting was created.
  • Foldable motor-beam connectors were found on Alibaba and six pieces ordered — cheaper than the RJX Hobby options investigated earlier.
  • Flight controller, GPS hardware, another camera, and an HM30 unit were received/ordered; most remaining test-flight parts were ordered during June.

Relevant work: issues #7, #14, #35, #38, #39, #40, #50.

Caribou Hub / System Unit

Alex completed basic development of Caribou Hub and the Caribou System Unit. Deployment is now straightforward via package release downloads and setup executables. Remaining work — testing, usage-based feedback, modifications, and cleanup — is waiting on hardware development to catch up (issue #52).

Phase 1 flight preparation

July is the final month of Caribou Phase 1, and the team’s target is a first flight:

  • Conservative test sequence: normal ground test first, then a tethered hover-style flight.
  • Test site not yet locked; Transport is planned on an open trailer.
  • Safety measures under discussion: battery-powered strobe/position lights for PT1, motor/prop covers for transport and handling, and 3D-printed corner feet. Parachute integration was discussed and deferred (more likely Phase 2).

4. July Priorities

  1. Finish the PT1 build as PCBs and ordered parts arrive.
  2. PT1 ground test.
  3. PT1 hover flight — including Caribou Hub testing and individual PCB testing.
  4. Documentation cleanup (PCB docs, README, kill-switch behavior notes).
  5. Coordinate studies for PT2.
  6. Phase 1 document preparation.

5. Budget

June contributor streams (June 1 – July 1, funded from the Caribou Safe on June 17):

Contributor Stream amount
Julius 9,000.00 USDC
KBM 3,840.00 USDC
Alex 2,880.00 USDC
Erick 2,560.00 USDC
Total streams 18,280.00 USDC

June reimbursements (executed from the Caribou Safe on July 6):

Contributor Item Amount
Julius Material (19 line items, see below) 4,920.25 USDC
Julius Freelancer: CBC_PCB review and improvements 1,112.49 USDC
Total reimbursements 6,032.74 USDC

The material reimbursement covers June’s PT1 hardware and PCB purchases. Largest items: foldable motor-arm connectors ($1,105), SIYI HM30 + A8 camera ($721), CBC pre-order components ($676), power and signal cabling ($510), and the CMAIN JLC PCB order ($420) — plus CM5 module and base board, GNSS, carbon-fiber tube, 2× Gigablox Nano Ethernet switches, cable lugs, connectors, rubber dampeners, adhesives, and a test heatsink.

Total June allocation: 24,312.74 USDC (streams + reimbursements).

6. Key Sources

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