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Initial release v1.1.0 — ESP32 automated telescope flat panel

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Firmware (Arduino Nano ESP32 / PlatformIO):
- Native ASCOM Alpaca CoverCalibrator REST API on port 11111
- Alnitak serial protocol on USB at 9600 baud (simultaneous with WiFi)
- MG995 servo cover mechanism with non-blocking state machine (D9)
- LED brightness PWM via IRLZ44N MOSFET, LEDC channel 0 (D3)
- 12V dew heater PWM via IRLZ44N MOSFET, LEDC channel 1 (D5)
- mDNS + UDP Alpaca discovery, WiFi watchdog reconnect
- SERIAL_DEBUG flag to silence debug output in USB-only mode

INDI driver (C++ / libcurl / nlohmann-json):
- WiFi mode: HTTP Alpaca via libcurl
- USB mode: Alnitak serial via POSIX termios
- LightBoxInterface + DustCapInterface + dew heater number property

Python controller (PyQt6):
- Dark-themed desktop app for direct manual control
- AlpacaBackend (requests) + AlnitakBackend (pyserial)
- PollWorker QThread; cover, brightness, dew heater panels
- QSettings persistence; auto serial port discovery

Docs:
- system-diagram.svg, wiring-diagram.svg (browser-renderable SVG)
- BUILD_NOTES.md with BOM, LM2596 calibration, power-on checklist
- WIRING.md quick-reference, README.md, CHANGELOG.md
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# ESP32 FlatPanel – Wiring & BOM
## What to buy
| Item | Purpose | Notes |
|------|---------|-------|
| IRLZ44N N-channel MOSFET × 2 | LED brightness + dew heater control | Logic-level: 3.3 V gate from ESP32 is sufficient. One per load. |
| 100 Ω resistor × 2 (1/4 W) | MOSFET gate current limiting | One per MOSFET |
| 10 kΩ resistor × 2 (1/4 W) | MOSFET gate pull-down | Ensures loads are off at boot |
| White LED strip or panel (12 V) | Flat-field illumination surface | High-CRI (Ra > 90) recommended. Size to scope aperture. |
| Frosted acrylic sheet | Light diffuser | 3 mm thick, cut to scope outer diameter |
| Dew heater element (12 V, ~5-10 W) | Prevents flat panel misting up | Nichrome wire mat, resistive heating tape, or commercial dew strap cut to fit. ~24 Ω for 6 W at 12 V. |
| LM2596 or MP1584 buck converter module | 12 V → 5 V for servo | Set output to 5.0 V before connecting |
| 12 V DC power supply (≥ 4 A) | Powers everything | LED 2 A + dew heater 0.5 A + servo 1 A peak |
| 1N4007 diode | Optional: reverse-polarity protection on 12 V input | |
| Prototype / strip board | Assembly | |
| JST connectors or screw terminals | Clean connections | |
| Aluminium or 3D-printed enclosure | Mechanical housing | |
---
## Component roles
| Component | Role |
|-----------|------|
| Arduino Nano ESP32 | Main controller: WiFi, Alpaca server, PWM, servo |
| MG995 servo | Rotates the flat panel lid in / out of the telescope light path |
| SG90 micro servo | Spare / future use (e.g., secondary aperture cover) |
| 28BYJ-48 stepper | Spare / future use (e.g., precision ND-filter wheel for extra dimming) |
| IRLZ44N MOSFET | Controls LED strip power via PWM from ESP32 |
---
## Wiring diagram
```
12 V PSU ──────────────────────────────────────────── 12 V rail
│ │
│ LM2596 buck (set to 5 V) │
├──[IN+]──[OUT+]──────────────── 5 V rail │
│ [IN-]──[OUT-]─────────────── GND rail │
│ │
└── GND ──────────────────────── GND rail │
│
┌─────────── Arduino Nano ESP32 ───────────────────┐ │
│ VIN ◄──── 5 V rail │ │
│ GND ◄──── GND rail │ │
│ │ │
│ D9 ──────────────────────────► MG995 Signal │ │
│ 5 V rail ─────────────────────► MG995 VCC (5V) │ │
│ GND ──────────────────────────► MG995 GND │ │
│ │ │
│ D3 ──[100 Ω]──► MOSFET-A Gate (LED) │ │
│ GND ──[10 kΩ]──► MOSFET-A Gate (pull-down) │ │
│ MOSFET-A Source ──► GND rail │ │
│ MOSFET-A Drain ──► LED- │ │
│ │ │
│ D5 ──[100 Ω]──► MOSFET-B Gate (dew heater) │ │
│ GND ──[10 kΩ]──► MOSFET-B Gate (pull-down) │ │
│ MOSFET-B Source ──► GND rail │ │
│ MOSFET-B Drain ──► Heater- │ │
└──────────────────────────────────────────────────┘ │
│
LED strip/panel: LED+ ◄────────────────── 12 V rail ──┤
LED- ◄────────────────── MOSFET-A Drain
│
Dew heater: Heater+ ◄────────────────── 12 V rail ───┘
Heater- ◄────────────────── MOSFET-B Drain
```
### MOSFET pinout (IRLZ44N TO-220, flat face towards you)
```
Gate | Drain | Source
1 2 3
```
Connect:
- Gate (1) → 100 Ω → D3, with 10 kΩ from Gate to GND
- Drain (2) → LED strip negative lead
- Source (3) → GND rail
---
## Servo signal cable colours (standard)
| Colour | Signal |
|--------|--------|
| Brown / Black | GND |
| Red | VCC (5 V) |
| Orange / Yellow / White | Signal (PWM) |
---
## Pin summary
| ESP32 pin | Function | Config define |
|-----------|----------|---------------|
| D9 | MG995 servo signal | `SERVO_PIN` |
| D3 | LED PWM (MOSFET-A gate) | `LED_PWM_PIN` |
| D5 | Dew heater PWM (MOSFET-B gate) | `DEW_HEATER_PIN` |
---
## Dew heater element sizing
| 12 V supply | Resistance | Power | Suitable for panel size |
|-------------|------------|-------|------------------------|
| 48 Ω | 3 W | Up to 3″ aperture |
| 24 Ω | 6 W | 4-6″ aperture (recommended) |
| 12 Ω | 12 W | 8″+ aperture |
Use nichrome wire, resistive heating tape, or a commercial dew strap wound flat under the acrylic diffuser. The MOSFET PWM keeps average power proportional to the 0-100 % setting — you do not need to match exact resistance; just aim for 5-10 W at 12 V.
---
## Choosing between WiFi and USB mode
| | WiFi (Alpaca) | USB Serial (Alnitak) |
|-|--------------|---------------------|
| Cable required | No | Yes (USB-A to USB-C) |
| Works with | ASCOM Remote, our INDI driver | N.I.N.A. built-in, SGPro, APT, indi_flipflat, our INDI driver |
| Dew heater control | Via Alpaca Action (our driver) | Via custom T/U serial commands (our driver only) |
| Debug output | Set `SERIAL_DEBUG true` | Set `SERIAL_DEBUG false` |
| Discovery | mDNS + UDP broadcast | COM port / /dev/ttyUSBx |
For USB mode, edit `config.h` and set `SERIAL_DEBUG false` before flashing, then open the COM port at **9600 baud** in your software.
---
## First-time setup checklist
1. Set LM2596 output to **5.0 V** (measure with multimeter) *before* connecting servo.
2. Edit `firmware/src/config.h` — set `WIFI_SSID`, `WIFI_PASSWORD`.
- For USB-only use: also set `SERIAL_DEBUG false`.
3. Adjust `SERVO_OPEN` / `SERVO_CLOSED` angles for your mechanical setup.
4. Flash firmware via PlatformIO: `pio run -t upload`.
5. **WiFi mode**: open Serial Monitor (9600 baud) — note the printed IP address, then browse to `http://<IP>:11111/management/v1/configureddevices`.
6. **USB mode**: connect to the COM port at 9600 baud and send `>P000` — you should receive `*P19000`.
---
## ASCOM setup (Windows)
1. Install [ASCOM Platform 6.6+](https://ascom-standards.org/Downloads/Index.htm).
2. Install [ASCOM Remote](https://github.com/ASCOMInitiative/ASCOM.Alpaca.Simulators/releases) (acts as Alpaca → COM bridge).
3. In ASCOM Remote, add a **CoverCalibrator** device pointing to `http://esp32-flatpanel.local:11111`.
4. In your imaging software (N.I.N.A., SGPro, APT) select the "ASCOM Remote CoverCalibrator" driver.
---
## INDI setup (Linux / Raspberry Pi)
```bash
# Build dependencies
sudo apt install libindi-dev libcurl4-openssl-dev nlohmann-json3-dev cmake
# Build
cd flatpanel/indi-driver
cmake -B build -DCMAKE_INSTALL_PREFIX=/usr
cmake --build build -j$(nproc)
sudo cmake --install build
# Run (KStars/Ekos will load it automatically once installed)
# Or manually:
indiserver indi_esp32_flatpanel
```
In KStars → Ekos, select **ESP32 FlatPanel** in the Aux device drop-down.
- **WiFi mode**: select "WiFi / Alpaca" in the Connection Mode switch, enter the host (`esp32-flatpanel.local`) and port (11111), then connect.
- **USB mode**: select "USB Serial (Alnitak)", enter the serial port (`/dev/ttyUSB0` or `/dev/ttyACM0`), then connect. The dew heater slider is available in both modes.
**Alternative for USB mode (no custom driver needed):**
The existing `indi_flipflat` driver (ships with INDI) speaks standard Alnitak and will control brightness and cover. It will not control the dew heater — use our driver for that.
```bash
indiserver indi_flipflat
# Select port /dev/ttyUSB0, baud 9600
```