📄 docs: Add readme

README.md

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+# ESP32 "CYD" ThermoPro Bridge
+
+A proof-of-concept bridge that reads temperature data from a **ThermoPro TP930** (among others) Bluetooth BBQ thermometer and ships it to a self-hosted HTTP API for storage and display.
+
+## Architecture
+
+```plain
+ThermoPro TP930 (BLE)
+        │
+        ▼
+thermopro_cli.py  ←── BLE reader (reverse-engineered protocol, Linux only)
+        │
+        ▼
+  bridge_poc.py   ←── polls CLI, normalizes payload, POSTs to API
+        │
+        ▼
+  receiver.php    ←── stores latest reading + NDJSON log, serves status page
+```
+
+## Components
+
+### `thermopro_cli.py`
+
+Local copy of the [thermopro-cli](thermopro-cli/) tool. Communicates directly with the ThermoPro thermometer over BLE using a reverse-engineered protocol. Outputs probe temperatures, battery level, and unit as JSON.
+
+### `bridge_poc.py`
+
+Polling bridge that:
+
+1. Calls `thermopro_cli.py` on a configurable interval
+2. Normalizes the raw CLI output into a structured payload
+3. POSTs the reading to the configured HTTP endpoint with a shared secret token
+
+### `receiver.php`
+
+Minimal PHP API server that:
+
+- `POST /api/thermopro/readings` — accepts and validates a reading, writes it to `data/latest.json` and appends to `data/readings.ndjson`
+- `GET /api/thermopro/latest` — returns the most recent reading as JSON
+- `GET /` or `GET /status` — HTML status page (auto-refreshes every 10 seconds)
+
+## Data Format
+
+Each reading payload looks like:
+
+```json
+{
+  "deviceId": "tp930-smoker",
+  "device": "ThermoPro TP930",
+  "mac": "C9:48:1D:B1:E1:E7",
+  "connected": true,
+  "battery": 90,
+  "unit": "F",
+  "probeCount": 4,
+  "probes": [
+    { "id": 1, "name": "Probe 1", "temperature": 266.2, "connected": true },
+    { "id": 2, "name": "Probe 2", "temperature": null, "connected": false },
+    { "id": 3, "name": "Probe 3", "temperature": null, "connected": false },
+    { "id": 4, "name": "Probe 4", "temperature": null, "connected": false }
+  ],
+  "readingTime": "2026-06-06T12:00:00+00:00",
+  "bridgeTime": "2026-06-06T12:00:01+00:00",
+  "source": "thermopro_cli"
+}
+```
+
+## Requirements
+
+- **Bridge host:** Linux with Bluetooth (BlueZ), Python 3.8+, `bleak` library
+- **API server:** PHP 8.x with write access to the `data/` directory
+
+## Setup
+
+### 1. Install Python dependencies
+
+```bash
+pip install bleak
+```
+
+### 2. Configure the receiver
+
+Deploy `receiver.php` to a PHP-capable web server. Set the `THERMOPRO_BRIDGE_TOKEN` environment variable (or it defaults to `dev-secret`):
+
+```bash
+export THERMOPRO_BRIDGE_TOKEN="your-secret-token"
+```
+
+### 3. Run the bridge
+
+```bash
+python bridge_poc.py \
+  --cli thermopro_cli.py \
+  --endpoint https://your-server/api/thermopro/readings \
+  --token your-secret-token \
+  --device-id tp930-smoker \
+  --mac C9:48:1D:B1:E1:E7 \
+  --interval 15
+```
+
+**Options:**
+
+| Flag | Default | Description |
+| --- | --- | --- |
+| `--cli` | `thermopro_cli.py` | Path to `thermopro_cli.py` |
+| `--endpoint` | `http://127.0.0.1:8000/api/thermopro/readings` | API endpoint |
+| `--token` | `dev-secret` | Shared token (`X-Bridge-Token` header) |
+| `--device-id` | `tp930-smoker` | Stable identifier for this device |
+| `--mac` | `C9:48:1D:B1:E1:E7` | ThermoPro BLE MAC address |
+| `--interval` | `15` | Polling interval in seconds |
+| `--once` | — | Read and POST once, then exit |
+
+### Finding your device's MAC address
+
+```bash
+python thermopro_cli.py scan
+```
+
+## Data Storage
+
+| File | Contents |
+| --- | --- |
+| `data/latest.json` | Most recent reading (overwritten each poll) |
+| `data/readings.ndjson` | Append-only log of all readings (newline-delimited JSON) |
+
+## Security
+
+- The API endpoint is protected by a shared secret sent as the `X-Bridge-Token` request header.
+- Use HTTPS for the endpoint in production to keep the token confidential.
+- The token is compared with `hash_equals()` to prevent timing attacks.