# SkyLogic AeroAlign

Wireless RC setup platform for two related jobs:

- AeroAlign: digital incidence, reference-angle and differential measurement
- CoG Scale: center-of-gravity measurement using load cells

Both parts are intended to run in the same ESP32 ecosystem and talk to the same Master over ESP-NOW.

## Current State

Implemented now:

- Master firmware with WiFi AP, REST API and existing web UI
- IMU Master and IMU Slave support with robust MPU6050 access
- shared telemetry protocol for multiple device types
- UI support for both IMU nodes and future CoG scale nodes
- battery monitoring with optional hide/disable behavior on unsupported Master hardware

Prepared but not fully implemented yet:

- dedicated HX711-based CoG scale firmware
- model profiles with support spacing, leading-edge offset and target CoG
- scale calibration workflow in the web UI

## Architecture

```
IMU Slave(s) ------\
                    \
CoG Scale Node(s) ----> Master ESP32 ----> WiFi AP ----> Browser UI
                    /
Master local IMU --/
```

### Device roles

- `Master`
  - hosts `SkyLogic-AeroAlign`
  - receives ESP-NOW telemetry
  - serves the web UI and REST API
  - can also have its own MPU6050
- `IMU Slave`
  - remote angle node
  - sends pitch, roll and yaw fields as angle telemetry
- `CoG Scale`
  - future load-cell node
  - will send front weight, rear weight and computed CoG in the same shared packet

## Telemetry Protocol

The shared packet format is defined in [telemetry_protocol.h](firmware/common/telemetry_protocol.h).

Device types currently defined:

- `DEVICE_TYPE_IMU`
- `DEVICE_TYPE_COG_SCALE`
- `DEVICE_TYPE_HYBRID`

For IMU nodes:

- `pitch`, `roll`, `yaw` are angles

For CoG scale nodes:

- `pitch` => front support weight in grams
- `roll` => rear support weight in grams
- `yaw` => CoG position in millimeters

## Hardware Overview

### IMU nodes

Use:

- ESP32-C3 or ESP32-S3
- MPU6050
- LiPo, charger and 3.3V supply
- optional battery divider depending on node

See [sensor_node_wiring.md](hardware/schematics/sensor_node_wiring.md).

### CoG scale

Planned hardware stack:

- ESP32-C3 or ESP32-S3
- two HX711 boards
- two load cells
- rigid support spacing and repeatable fixtures

See [cog_scale_wiring.md](hardware/schematics/cog_scale_wiring.md).

### BOM

The BOM is now maintained as a current component overview instead of placeholder shop links:

- [bom.csv](hardware/schematics/bom.csv)

## Firmware Layout

### Existing

- [firmware/master](firmware/master)
- [firmware/slave](firmware/slave)
- [firmware/common](firmware/common)

### Planned

- `firmware/cog_slave`
  - HX711 reading
  - tare and scale calibration
  - CoG computation
  - ESP-NOW transmission as `DEVICE_TYPE_COG_SCALE`

## Build

Master:

```bash
cd firmware/master
pio run
```

Slave:

```bash
cd firmware/slave
pio run -e esp32-s3
pio run -e slave2-s3
```

## Current Configuration Notes

### Slave Master MAC

The Slave now reads the Master MAC from [config.cpp](firmware/slave/src/config.cpp), not `config.h`.

### Master battery monitoring

On ESP32-S3 Master boards the battery ADC path is optional. If the divider is not fitted, the firmware and UI hide the battery value instead of showing dummy data.

## CoG Math

With front and rear supports spaced by `L`:

`x_cog_from_front_support = rear_weight / (front_weight + rear_weight) * L`

If the front support is offset from the wing leading edge:

`x_cog_from_leading_edge = support_offset_from_leading_edge + x_cog_from_front_support`

The current design note is in [AEROALIGN_COG_INTEGRATION.md](docs/AEROALIGN_COG_INTEGRATION.md).

## Workflow Plan

The planned operating workflow and the recommended hardware roles are documented in:

- [WORKFLOW_AND_SYSTEM_PLAN.md](docs/WORKFLOW_AND_SYSTEM_PLAN.md)
- [AIRCRAFT_PROFILE_MODEL.md](docs/AIRCRAFT_PROFILE_MODEL.md)

## 3D Printed Parts

The CAD readme now covers both IMU parts and planned CoG fixtures:

- [hardware/cad/README.md](hardware/cad/README.md)

## Recommended Next Work

1. Add `firmware/cog_slave` with HX711 support.
2. Add tare and calibration endpoints in the Master API.
3. Add a dedicated CoG tab in the web UI.
4. Add aircraft profiles in NVS.
5. Finalize mechanical design for the two support fixtures.