Add Airthings BLE documentation (#23922)

Co-authored-by: Franck Nijhof <frenck@frenck.nl>
Co-authored-by: Franck Nijhof <git@frenck.dev>

source/_integrations/airthings_ble.markdown

@@ -0,0 +1,51 @@
+---
+title: Airthings BLE
+description: Instructions on how to set up Airthings Devices over Bluetooth LE.
+ha_category:
+  - Environment
+  - Sensor
+ha_release: '2022.11'
+ha_iot_class: Local Push
+ha_codeowners:
+  - '@vincegio'
+ha_domain: airthings_ble
+ha_bluetooth: true
+ha_platforms:
+  - sensor
+ha_config_flow: true
+ha_integration_type: integration
+---
+
+Integrates Airthings BLE sensors into Home Assistant.
+
+[Airthings](https://www.airthings.com/) provide different sensors for measuring the air quality. The focus specially on Radon sensors.
+
+Requires Airthings hardware and a compatible Bluetooth dongle.
+
+{% include integrations/config_flow.md %}
+
+The Airthings BLE integration will automatically discover devices once the [Bluetooth](/integrations/bluetooth) integration is enabled and functional. This will include the device name and its serial number.
+
+There are two ways of retrieving the 10-digit serial number of a Wave device:
+1. At the back of the device, located under the magnetic backplate.
+2. Airthings app: **Device settings -> Device info -> Serial Number**
+
+This integration uses the last 6 digits of the serial number.
+
+## Supported Devices
+
+- Wave
+- Wave+
+- Wave mini
+
+## Sensors
+
+Sensor entities added to Home Assistant, depending on the device model:
+- Humidity
+- Illuminance
+- Pressure (relative depending on home elevation)
+- Radon 1-day and longterm average, as well as levels
+- Temperature
+- VOC
+- Co2
+- Battery