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Vector edited this page Apr 28, 2026 · 6 revisions

April 7, 2026

Caribou Call (First Meeting) — Recording

Attendees: far1no, thomasg, errrks.eth, alperenag, kbmollysuh, zeynepb5793

  • Current State — Frame is built with motors mounted (photo from November). Old battery holders still in the frame from the previous battery design — Julius will cut them out. CAD assembly shown in Fusion with updated battery layout.

  • Architecture Overview

    • Batteries insert from the top into the frame; each gets its own battery PCB
    • Central signal PCB (similar to Quiver main PCB but without motor power distribution) — receives 12V and 5V from each battery for redundancy
    • Battery PCBs: similar to Quiver but higher-rated, with onboard DC-DC converters
    • Power redundancy: MOSFET-based 3-source 12V combining (carried over from Feather's power distribution board) will be added to the center PCB
    • All remote-controlled via autopilot — no physical pilot toggles (unlike Feather, which was designed with a pilot in mind)

  • Team Availability

    • Option 1 (time + energy): Erick, Alex, KBM
    • Option 2 (small tasks): Alperen, Zeynep, Thomas
    • Julius to reach out individually for time estimates
    • Erick: limited availability in April until he moves out of Bay City; will keep up via recordings and GitHub async

  • Meeting Cadence — Weekly on Tuesdays before the Quiver call. Detailed technical sessions can be scheduled separately with fewer people as needed.

  • Testing / V2 Plans

    • V1 frame has suboptimal space utilization for the new battery layout — not worth replicating
    • Motor beam connectors are welded (labor-intensive) — will be improved in V2
    • Thomas / Javelina will build V2 after first test flight: "I'd love to build one"
    • Thomas to do US market research / licensing study (self-assigned)

  • Parachute — Never tested on Feather; this frame could be used to gain parachute deployment experience for future builds

  • Tethered Ground Power — Thomas raised it as potentially useful for firefighting. Complex on Caribou (6 independent power units). Consensus: test on Quiver first, then scale up. KBM noted it would require very high-power tethering, likely 3-phase AC-to-DC with serious protection circuitry.

  • Payload Ideas — KBM floated brush bullet dispensing; Thomas more interested in granular or liquid dispensing for Javelina use cases

  • First Flight Target — Julius estimating summer (July-ish). Erick asked about timing relative to "Chicken Festival" (late October) — Julius expects to be flying well before then.

  • Longshot Battery Update — Thomas asked about status. Julius: ready to start; a friend has agreed to work on the BMS. Thomas: "I'm very eager — I'll manufacture and test whatever we need." Julius to set up a call with Ben for onboarding.

  • Quiver Standup (informal) — No Quiver call today. Quick check: no one had open issues. Thomas heading to the workshop.

  • Open Items

    • Julius: remove old battery holders from frame; reach out to team individually for time commitments
    • Julius: set up onboarding call with Ben (Longshot BMS contributor)
    • Thomas: US market research / licensing study for heavy-lift operations
    • Thomas: research tethered ground power (talk to firefighting contacts; test on Quiver first)

April 14, 2026

Caribou Call — Recording

Attendees: far1no, errrks.eth, thomasg, kbmollysuh, alperenag, 21stCenturyAlex

  • Battery Mounting Brackets (KBM)

    • KBM started designing slide-in brackets for top-loading batteries
    • Material: bent aluminum (no welding)
    • Concern about adding holes to the airframe — Julius: 2–4 per battery is fine; reuse existing holes where possible
    • Target: prototype drawing by next week

  • Battery Connector PCB (Julius)

    • Layout nearly complete; struggling to find the correct 4-pin center connector for the slide-in battery interface (different geometry from Quiver)
    • May need to contact Molex directly

  • QuiverHub Port for Caribou (Alex)

    • Alex started a Caribou-specific port of QuiverHub — local deployment with Caribou-specific features
    • Julius agrees separation makes sense for now

  • Flight Controller — Alex suggested upgrading the FC. Julius: use Quiver's Pix32v6 + FC PCB for first test flight (already designed for swappable FCs). Thomas: good to log hours on Quiver hardware before risking expensive upgrades. Upgrade later.

  • Foldable Motor Arm Connectors (V2 discussion)

    • Thomas researched for ~1 hour: downward-folding vertical hinges structurally best (thrust goes into hard stop)
    • RJX Hobby sells 50mm side-folding connectors — similar to landing leg adapters; quick option for V2
    • Thomas added it back to his to-do list

  • 50L Spraying Drone Reference

    • Julius chatted with the battery seller — they shared a 50L agricultural spraying drone kit (assembly required)
    • Uses Hobbywing motors, CX-13 (~57kg thrust/motor) — 50L payload claim seems ambitious; likely ~50kg MTOW not payload
    • Interesting features: weighing modules (3 per arm) for payload measurement, flow meters for liquid dispensing
    • Frame is very minimal compared to Caribou
    • Caribou still ~4× bigger capacity
    • Thomas: weighing modules useful for Quiver too (payload verification, flow rate for liquid/granular dispensing)

  • Thomas — Market Research — Will find time to talk to Kade and continue US market research for heavy-lift operations.

  • Quiver Meeting — Confirmed for tomorrow (not today). No Quiver call this day.

  • Open Items

    • KBM: battery mounting bracket prototype drawing (next week)
    • Julius: find correct 4-pin connector for battery PCB (contact Molex if needed)
    • Thomas: talk to Kade, continue US market research
    • Thomas: research foldable motor arm connectors further
    • Alex: continue Caribou QuiverHub port

April 28, 2026

Caribou Call — Recording

Attendees: far1no, errrks.eth, alperenag, kbmollysuh, thomasg

  • Battery Mounting / Connector Sourcing

    • Julius reviewed KBM's battery mounting work
    • Battery mounts now have four screw points each, mirrored across batteries
    • There is enough space left for the PCB enclosure
    • Julius found cheaper battery connector options from the original/alternate manufacturers
    • Julius prefers a right-angle connector variant
    • Some variants have three middle contacts; Julius thinks the extra middle contact can be left unused because spacing appears workable
    • Alibaba and extension-cable sources may be viable
    • KBM may check local Shenzhen/Huaqiangbei sources and asked Julius for the link/email context

  • Repository / Project Organization

    • Julius created an engineering folder in GitHub
    • Structure includes CAD/build123d and electronics folders
    • Each PCB has its own folder
    • Goal: each KiCad project should include its own local library for non-standard components
    • This avoids Quiver's old issue where symbols/footprints lived only on Julius's machine and makes projects easier for others to open

  • Battery Connector PCB Architecture

    • Julius is designing a battery connector PCB similar to Quiver's but upgraded
    • Major change: add an onboard MCU so the battery connector PCB handles precharge, MOSFET/SSR closing, and battery protocol bridging
    • Flight controller should only send a kill/shutdown signal in emergencies
    • Normal line state has no voltage; pulling the controller pin high shuts down the network
    • Proposed MCU: ESP32-C3
    • ESP32-C3 provides Wi-Fi/Bluetooth if needed for local parameter checks or a small app and still leaves about 9 spare pins
    • Caribou has six batteries, and BMS protocol cannot be assumed to be DroneCAN, so each PCB may need to bridge/convert battery communication to DroneCAN

  • Power Architecture

    • Internal supplies: 5 V internal supply and 3.3 V for MCU/control logic
    • Internal ground is not isolated from battery negative
    • Each battery board will send an isolated 12 V supply to the main PCB
    • Julius chose a preliminary 10 A / 120 W per battery target for the 12 V avionics/redundancy supply
    • This follows/extends the redundant power supply concept used in later Feather work

  • Current Ratings / PCB Design Targets

    • Motor current at ~50% throttle is under ~50 A
    • 200 A is treated as peak, not expected continuously
    • Julius thinks designing the PCB for 100 A should be sufficient, with proper fuse design
    • Main PCB work is next

  • KiCad / Freelancer Workflow

    • Julius handed the battery connector PCB task to a new Fiverr freelancer
    • Freelancer is expected to send schematics this week and layout about a week after schematic review
    • Erick offered to review schematics
    • Julius hopes Vector can also help review, especially with KiCad integration tools
    • Desired AI/KiCad help includes schematic/PCB review, footprint/rating/pin compatibility checks, design-rule setup consistency, trace widths, layer descriptions, and signal descriptions
    • Julius has PCB docs/pinout/architecture files in the repo for review

  • Cabling / CAD Work

    • Julius suggested Erick can start cabling work in CAD, especially motor-to-battery wiring
    • Erick can import the design into Inventor and leave final PCB connection details flexible

  • Quiver SSR / Lua Script Note

    • Julius asked Thomas about flying with the Lua script for closing the SSR
    • Julius inspected PCBs Thomas sent: precharge resistors appear overheated/discolored, one has a solder blob, and measured no continuity; likely burned open internally
    • The short appears to come from the DC-DC converter
    • Julius suspects resistor overheating may have pulled main PCB terminal voltage low, causing the 12 V regulator/DC-DC converter to fail or overheat
    • Thomas will install/drop the Lua script on the relevant flight controller next time he sees Boosh/Ben and has emphasized closing the relay as soon as possible

  • Open Items

    • Julius: send KBM connector link/email/source context
    • KBM: check local connector availability/samples if useful
    • Julius: continue main PCB work
    • Freelancer: deliver battery connector PCB schematics this week
    • Erick: review battery connector PCB schematics when available
    • Vector: help review KiCad schematics/PCB when available, starting with inspection before edits
    • Erick: start Caribou cabling work in CAD, especially motor-to-battery paths
    • Thomas: install/use Lua SSR-closing script on Boosh/Ben flight controller

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