ESPHome for the Qingping Air Monitor Lite (CGDN1)

[!WARNING] Installing this can brick your monitor, and there are no guarantees. If an image fails to boot, the only way back is a USB-TTL (3.3 V UART) adapter on the ESP32 inside the case, and getting there means taking out the glued-in screen. Use at your own risk.

New

• Bluetooth proxy for Home Assistant, advertisements only, with a runtime "Bluetooth" switch. It is passive on purpose: proxied GATT connections tripped an ESP32 Bluetooth controller assert after about 2 h of retries to a device that kept failing.
• Measured heat model (cgdn1_tcomp, select "Heat model"): a two-stage display heat model scaled by brightness, plus a Bluetooth heat term, instead of stock's −1 °C display ramp. Every constant is a Home Assistant config number, with "Display heat estimate" / "Bluetooth heat estimate" sensors so you can tune it while watching graphs. "Stock" keeps the exact stock behaviour.
• Humidity at constant vapour pressure in the Measured model (Magnus 17.62 / 243.12). Stock's transfer reads about 4–6 %RH high at the usual self-heat.
• PM1.0 page and an info page in the page ring: PM1.0 → PM2.5 → PM10 → CO2 → T → RH → info. The info page shows version, build, MAC, WiFi and signal, IP, fallback AP, Bluetooth and uptime, then moves on after 10 s.
• Screen messages over MQTT (optional, off by default): notifications and questions on <name>/notify, answered by a tap or swipe and reported on <name>/notify/response. Build with esphome -s mqtt_messages true compile cgdn1.yaml and fill in the mqtt_* secrets. The README has a Home Assistant automation example.
• README brick warning. docs/install.md: pass the same -s options to esphome logs as to the build.

Upgrading from v0.1.0

• With ESPHome's own OTA (trial mode off), build and install as usual.
• In trial mode, return to stock first, then push with tools/cgdn1_ota_push.py as in docs/install.md. ESPHome's own OTA would overwrite stock.
• New secrets only if you turn on MQTT messages (mqtt_broker, mqtt_username, mqtt_password).

No prebuilt binary: the image embeds your WiFi credentials and API key, so build it yourself with ESPHome 2026.9.1.

Known limitations

• Tested on one unit: stock 4.8.5, display panel variant B. This release was installed with tools/cgdn1_ota_push.py in trial mode; the trial mark and every feature above work on that unit.
• Not yet tested on hardware: pushing straight from unmodified stock, the first boot with trial mode off, the "Boot other firmware slot" button, panel variant A.
• The heat model defaults come from one unit; yours may differ, so tune from Home Assistant.