About¶

Quick-reference specification for libdrone Pro — the 6-inch research and commercial variant. The Pro is a flying payload platform with a documented open interface standard and an optional onboard intelligence layer that no closed commercial platform offers: a Raspberry Pi Zero 2W that aggregates flight data, sensor readings, and FC telemetry into contextual alerts — transmitting only what matters, when it matters, to a live map on the operator's tablet.

Covers key parameters, architecture summary, GX12-7 connector polarity, print and build notes, UART assignment, and version history.

libdrone Pro — Platform Specification¶

Version: V2.4.6 | March 2026 Full spec: reference/LD_-_Master_Specification_v246.md Variables: reference/LD_-_Variables_v246.md

Quick Reference¶

Architecture Summary¶

TOP:    Backplane (187×50mm PETG lattice, ~65% open, payload interface)
MIDDLE: Platform (283mm PETG, stepped 40/50mm, battery rails, GX12-7 chimneys)
BOTTOM: X body sandwich (PETG/PCCF/PCCF/PCCF/PETG, 16mm total)
        Arms: 4× PETG shaft + 2× PETG tab each, CF rod channels

The Intelligence Layer — What Sets Pro Apart¶

Every libdrone Pro is built Pi-ready. A 6mm bay above the Backplane, a pre-wired 4-wire companion harness to FC UART6, and a dedicated buck converter on the battery rail are installed during build — whether or not a Pi is ordered.

When the LCM-1 option (Pi Zero 2W) is fitted, the platform gains something no DJI, Pilotix, or VC-backed commercial drone offers out of the box:

Contextual intelligence on the airframe.

The Pi sees everything simultaneously — GPS position and altitude from the FC, attitude and battery state from the companion UART, and sensor readings from the payload via WiFi. It applies threshold logic in flight:

• Only transmit when PM2.5 changes by more than 5 µg/m³
• Only flag a radiation reading when above 50m AGL and away from ground contamination
• Combine position, wind direction from flight path, and sensor spike into a single alert string
• Send one meaningful event to the ground station instead of a wall of 2Hz updates

The filtered data travels through the existing ELRS radio link — no additional hardware on the drone. The operator's tablet, connected to the TX16S WiFi backpack, sees live sensor events overlaid on OpenStreetMap. Position, altitude, battery, and payload readings — all in one picture, updating when something actually happens.

Pi-ready by default. Pi-fitted by mission. A sensor mapping mission that needs this intelligence: fit the Pi in 15 minutes. A quick survey flight that doesn't: leave the bay capped. Zero weight penalty for the missions that don't need it.

See: payloads/LD_-_LCM1_Spec_v100.md (LD-PAY-004) for full specification. See: build/LD_-_WBS_v246.md Phase 9 for commissioning procedure. See: build/LD_-_Software_v246.md §Pi Zero 2W Setup for OS configuration.

• Connector A (X=−25mm, Y=−66mm): signal/power — 5V, GND, UART4, I2C
• Connector B (X=+25mm, Y=−66mm): data/aux — UART5, AUX GPIO, GPS tap
• Drone side: GX12-7 MALE panel mount
• Payload side: GX12-7 FEMALE cable mount
• Chimney bore: D-D profile, 10.80mm flat-to-flat, 11.87mm OD
• Retention: double nut + Loctite 243 blue
• ICD: LD-PAY-002 v1.0.1 (released) — full hardware and software protocol specification
• Library: libdrone.py v1.0.0 — MicroPython payload API (OSD, GPS, Command, AUX, Logger)
• Reference hardware: PSB-1 Payload Shield Board (LD-PAY-003) — perfboard build guide

Companion Interface (Pi bay / LCM-1)¶

• Pi bay: 6mm PETG tray above Backplane — always printed on every Pro build
• Companion harness: 4-wire JST-SH, pre-wired during build, UART6 reserved as COMPANION
• Companion power: dedicated XL4016 buck converter, battery rail, independent of FC BEC
• LCM-1 option: Pi Zero 2W fits in bay — WiFi hotspot, MAVLink bridge, REST API, onboard logging
• Without Pi: cover plate in bay, companion harness capped. Zero functional penalty.

Reference Payloads¶

Key Documents¶

"In CAD as in life: measure twice, extrude once." — libdrone V2.4.6

Revision History¶