Detailed project description

Project overview

ArduStack AI AIO is an AI-assisted concept for a compact ArduPilot-compatible flight controller intended for small autonomous multirotors. The design uses three stacked, double-sided rigid PCBs, providing six usable component surfaces while maintaining a small overall footprint.

The stack physically separates radio-frequency equipment, sensitive flight-control electronics and high-current motor-control circuitry. This separation is intended to reduce electromagnetic interference, improve cooling and make individual sections replaceable during development.

This project is presently in the engineering-design stage. The stated specifications are design targets and have not yet been validated by a manufactured prototype.

Three-board architecture

Top RF and navigation board

The upper board carries the equipment that requires the clearest view of the sky and the greatest separation from motor-current noise.

It is planned to contain:

Multi-constellation GNSS receiver

GNSS patch antenna

ExpressLRS receiver

ELRS antenna connection

Magnetometer or electronic compass

Low-noise RF power filtering

All aerials are located on the upper surface. Antenna regions will use the ground-plane geometry and copper keep-outs required by their manufacturers rather than being covered by unrestricted shielding copper.

Middle flight-controller board

The centre board is the electrically quiet flight-computing layer.

It is planned to contain:

STM32H743 processor

ArduPilot-compatible hardware definition

Primary inertial measurement unit

Optional redundant IMU

Barometric pressure sensor

Flight-log memory

USB and SWD programming connections

Sensor and communications interfaces

Clean digital and sensor power supplies

The middle board also forms a grounded barrier between the RF board above and the high-current ESC board below.

Bottom power and downward-navigation board

The bottom board directly receives battery power and drives all four brushless motors. No separate four-in-one ESC board is required.

It is planned to contain:

Four integrated three-phase brushless ESC channels

Battery input

Current and voltage sensing

Power filtering and protection

MOSFET thermal copper areas

Downward-facing PMW3901 optical-flow camera

Downward-facing VL53L1X distance sensor

Motor connections positioned around the board perimeter

The initial power target is operation from a 1S or 2S LiPo/LiHV battery at up to approximately 12 A continuous per motor. This rating is provisional and must be confirmed through electrical, thermal and destructive-limit testing.

Cooling and shielding

Unused copper areas on the six PCB faces are used as grounded shielding and, where electrically appropriate, as thermal spreaders. Ground via stitching links the copper areas on opposite faces and creates shielding fences around sensitive or electrically noisy sections.

The ESC MOSFET regions use:

Large copper heat-spreading areas

Thermal-via arrays

Short high-current paths

Local power-plane separation

Direct airflow where possible

Switching nodes cannot be connected directly to grounded shielding. Their copper areas will therefore remain electrically separate while being surrounded by grounded shield regions.

Grounded mechanical structure

Four conductive metal spacer tubes and metal screws mechanically separate the boards. Plated mounting holes and exposed ground annuli connect the spacers to the ground system on every PCB.

The spacers form four vertical ground pillars through the complete stack, joining the grounded shield surfaces and providing short paths for high-frequency interference currents.

The spacers are not used as the primary motor-current return. Motor and battery currents remain on dedicated heavy-copper paths on the bottom board so that vibration or a loose mechanical joint cannot interrupt the power circuit or inject unnecessary noise into the upper boards.

Nonmagnetic nickel-plated brass hardware is preferred to reduce interference with the compass.

Intended capabilities

The completed controller is intended to provide:

ArduPilot Copter compatibility

Direct control and power delivery for four brushless motors

ExpressLRS command and telemetry communication

GNSS-based outdoor navigation

Optical-flow-assisted indoor positioning

Downward height measurement

Barometric altitude estimation

Compass heading

Flight-data logging

Compact installation in lightweight autonomous drones

Modular replacement of damaged or revised boards

Current development status

This page describes the intended architecture rather than a completed and tested product.

Work still required includes:

Final component selection

Power-budget calculations

Complete schematic design

PCB layout

Signal-integrity review

RF and antenna review

Thermal modelling

ArduPilot hardware-definition files

Bootloader and firmware testing

ESC firmware selection

Prototype manufacture

Bench testing

Motor testing

Vibration testing

GNSS and ELRS range testing

Optical-flow calibration

Initial tethered flight testing

Full flight validation

Gerbers, schematics, assembly files and measured performance data will be added only after the relevant design revision has been reviewed and tested.