Bounty: V1 Quiver Multispectral Camera Payload

Grants / Bounties
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1

Status: Open

Reward: $500 USDC (milestone based, see below) — not including camera cost. Camera will be sourced by the DAO.

Deadline: 45 days from concept approval

Apply: Reply with a concept sketch

Technical Contact: errrks.eth, errrks@arrowair.com

Overview

Project Quiver is a 25kg MTOW open-source quadcopter with hot-swappable payload interfaces, developed by Arrow Air. More at github.com/Arrow-air/project-quiver.

The goal of this bounty is to design and build a fixed nadir (straight down) mount for the MAPIR Survey3W RGN multispectral camera that integrates with the standard Quiver payload attachment interface. The payload must deliver regulated power to the camera and trigger image capture from the flight controller. Geotagging is handled by the camera’s built-in u-blox GPS.

Note: The Quiver payload interface carries CAN and Ethernet only — no serial/UART. ArduPilot GPS passthrough to the camera is not possible in V1. The camera’s onboard GPS is used for geotagging. This may be revisited in a future revision if mission requirements demand higher positional accuracy.

This is a V1 integration — no gimbal, no live downlink. Images are retrieved post-flight via Micro SD.

See the community discussion for background: Arrow Payload Systems — Multispectral Camera

Scope of Work

This bounty defines the functional requirements and known interface constraints. It does not fully specify every integration detail — working out how to achieve a complete, flight-ready integration is the core of what this bounty is paying for. The contributor is expected to identify and solve integration challenges independently, document their decisions, and flag any issues that require input from errrks.eth.

If you encounter an integration problem not covered in this document, make a reasonable engineering decision, document it, and note it in your Information Note.

Camera: MAPIR Survey3W RGN

Product page: Survey3W Camera - Red+Green+NIR (RGN, NDVI) - MAPIR CAMERA

Spec Value
Resolution 12MP (4,000 × 3,000 px)
Sensor Sony Exmor R IMX117
Bands Red (660nm) + Green (550nm) + NIR (850nm)
Lens 87° HFOV, f/2.8, 19mm equiv.
Dimensions 59 × 41.5 × 36mm
Weight 76g (with battery)
Power 5.2V, ~0.33A capturing
Trigger PWM 2000µs via HDMI port
Storage Micro SD (up to 512GB)
GPS u-blox (accepts NMEA via USB — not used in V1)
GSD 5.5 cm/px at 120m altitude

Technical Specifications

1. Mechanical Design

  • Attachment Point: Side attachment points only (left or right). The Quiver has two side attachment points at ±185.65mm from the airframe centerline. The mount must clip onto the exposed face of the standard Quiver side quick release plate (JMRRC aluminum plate) and must work on either side — design for symmetry or provide mirrored CAD variants for left and right. Reference the STEP file listed below for exact geometry.
  • Camera Orientation: Fixed nadir (lens pointing straight down). Because the mount attaches to the side of the airframe, the housing must extend the camera outward and downward to achieve a nadir orientation below the airframe body. Keep the bracket arm as short as possible — the longer the arm, the more bending stress on the quick release plate. No gimbal required for V1.
  • Camera Fit: Housing must securely hold the MAPIR Survey3W body (59 × 41.5 × 36mm) with access to the Micro SD slot for post-flight data retrieval.
  • Weight Target: Total assembly (housing, electronics, camera) under 350g.
  • Materials: 3D printed housing — PETG or Carbon Fiber Nylon preferred for durability.
  • Vibration Isolation: The housing must incorporate vibration damping between the camera and the mount (e.g., rubber grommets, silicone dampers, or equivalent). Document the isolation method and materials in the Information Note.
  • Environmental Conditions: The payload will be used in dusty environments (agricultural and land survey operations). The housing must provide at minimum IP5X dust protection — sealed seams, gaskets, or equivalent measures to prevent dust ingress into electronics and the camera body. The lens opening is exempt. Document the dust protection approach and test conditions in the Information Note.

2. Electrical & Control

  • Power Input: 12V DC from the Quiver Attachment Interface PCB (pin 10, +12V).
  • Camera Power: The MAPIR Survey3W must run entirely off drone power — the internal battery is not used in flight. The camera requires 5.2V regulated power. The bounty worker is responsible for designing the 12V → 5.2V conversion and determining the correct power input on the camera. Document the chosen regulator, efficiency at load, and thermal considerations in the BOM.
  • Trigger Input: FMU_CH7 (pin 12 on J1 Molex) — 3.3V GPIO from the Pix32 V6 flight controller.
  • Trigger Output: The camera expects a continuous servo PWM signal on the HDMI trigger pin: 1000µs = not triggered, 2000µs = shutter. The MCU must output PWM continuously — idle at 1000µs on startup and signal loss, and switch to 2000µs when FMU_CH7 goes high. Refer to MAPIR Survey3W documentation for the specific HDMI pin used for PWM trigger input — confirming the correct pin is part of this integration.
  • GPS: The camera uses its own built-in u-blox GPS for geotagging. No wiring required. Ensure the camera has a clear view of the sky — the nadir mount should not obstruct the GPS antenna on the camera body.
  • Microcontroller: A MCU (ATTiny, ESP32, or equivalent) is recommended to handle the GPIO → PWM trigger conversion. Must operate at 3.3V on the signal input pin. If using a 5V MCU, document the level shifting solution.
  • Connector to Attachment PCB: Payload must use the Molex 2045231201 mating connector to interface with J1 on the attachment PCB. Pre-crimped cables available from Mouser PN 538-79758-1149, no crimping required.
  • Connector to Camera: A PWM HDMI trigger cable is available from the camera supplier: Survey3 HDMI PWM Trigger + Exposure Strobe Cable - MAPIR CAMERA

3. Software Integration

  • MCU Firmware: Provide source code for the onboard MCU. The MCU must output a continuous servo PWM signal to the camera HDMI trigger pin at all times:
    • Idle state (default): 1000µs — output continuously on power on and signal loss
    • Trigger state: 2000µs — switch when FMU_CH7 GPIO has been held high for at least 50ms, then return to 1000µs when signal goes low

Electrical Interface — Quiver Attachment PCB

The payload connects via the 12 pin Molex locking connector (J1) on the attachment board.

  • Attachment PCB connector: Molex 2077601281 (12 pin, on the attachment board)
  • Payload side mating connector: Molex 2045231201 — pre-crimped cables available from Mouser PN 538-79758-1149, no crimping required

Relevant Pins (J1 — 12 pin Molex 2077601281)

Pin Signal Description Notes
6 GND Ground reference Pin 8 is also GND — both available
10 +12V Main 12V supply (always on) Step down to 5.2V for camera power
12 FMU_CH7 Flight controller trigger signal 3.3V GPIO — High = capture trigger

Power Notes

  • The +12V rail (pin 10) is always on when the system is powered. Step this down to 5.2V for the camera — a standard 5V regulator is not sufficient; the camera requires 5.2V specifically.
  • FMU_CH7 is a 3.3V GPIO signal. If using a 5V MCU, a level shifter is required on the signal input pin. ESP32 or ATTiny85 (at 3.3V) are recommended.
  • Size the regulator for at least 500mA continuous at 5.2V to handle capture + GPS load.

Deliverables

  1. CAD Files — Complete assembly in .step or Fusion 360 format, including 3D printable housing with Micro SD access port.
  2. BOM — Full bill of materials including every component, supplier, part number, and unit cost. Must be sufficient for another DAO member to independently source and replicate the build.
  3. Wiring Diagram / Schematic — Clear diagram showing: J1 (Molex 2077601281) → Molex 2045231201 harness → 5.2V regulator → camera power, and FMU_CH7 → MCU → HDMI trigger pin → camera.
  4. Firmware/Code — MCU source code with comments. Must handle: GPIO input reading, PWM trigger output, idle on startup and signal loss.
  5. Information Note — Brief document following AIP-5 standard covering:
    • Assembly steps
    • Test results (see Evaluation Criteria)

Milestone Payment Schedule

Milestone Payout Trigger
M1 — Concept Approval $150 (30%) Concept sketch, CAD, and electronics reviewed and approved by errrks.eth
M2 — Working Prototype $150 (30%) Video showing camera triggering and geotagged image retrieved from SD card
M3 — Final Acceptance $200 (40%) All deliverables submitted. Bench demonstration video showing full trigger-to-image cycle with valid GPS geotag, and physical fit confirmed against the quick release plate. Reviewed and approved by errrks.eth.

Payment is in USDC. Each milestone must be approved before the next begins.

Claim Process

This bounty operates on a claim and lock basis:

  1. Reply with a concept sketch.
  2. errrks.eth will review and approve or provide feedback within 5 business days.
  3. Once approved, the bounty is locked to that contributor and the 45 day clock starts.
  4. If the deadline is missed or the contributor withdraws, the bounty reopens.

Only one active claim at a time. Concept sketches from other contributors are welcome as community input for future iterations.

Revision Policy

If a submission does not pass evaluation at M3, the contributor has 14 days to address the feedback and resubmit. errrks.eth will provide written feedback specifying what must be corrected. If the revised submission still does not pass, errrks.eth will determine whether to extend, renegotiate, or reopen the bounty.

Evaluation Criteria

Evaluator: errrks.eth (errrks@arrowair.com)

Criteria Requirement
Fit Assembly must physically mount to the Quiver side attachment plate without modification to the plate. Camera must be held securely with nadir orientation. Demonstrated via physical fit check and documented in the Information Note.
Power Camera receives stable 5.2V under load. Document regulator choice and thermal behavior.
Trigger Camera successfully captures an image on each FMU_CH7 GPIO trigger during a simulated flight sequence.
GPS Tag Retrieved images contain valid GPS coordinates from the camera’s built-in GPS.
Vibration Isolation Housing must incorporate damping between camera and mount. Document method and materials used.
Dust Protection Housing must achieve at minimum IP5X. Document the sealing approach and test method used.
Simplicity Preference for commonly available off the shelf components to ensure DAO replicability.

Open Source Requirement

All work produced under this bounty must be released as open source upon submission. This includes CAD files, firmware, schematics, and documentation.

Submitting this bounty constitutes agreement to release all deliverables under the above licenses. Files should be contributed to the Arrow community repository or linked from a public GitHub repository.

Reference Files

Arrow Payload Systems

Quick Release Plate (Mechanical Interface)

Information Note Standard

Attachment Interface PCB

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