Sensy-One AirDot – CO₂, Particulate Matter, and VOC Monitor with ESPHome, MQTT, and Flight Radar

Indoor Air Quality You See, Understand, and Control

Poor indoor air quality is rarely noticeable but directly impacts sleep, concentration, and health. The AirDot from Sensy-One combines a Sensirion SEN66 air quality sensor with a round 480x480 color display, an ESP32-S3 processor, and ESPHome firmware. The device measures, explains the meaning of the values, and advises on the best course of action: monitor, ventilate, limit exposure, or take immediate action.

Power and Connectivity

The AirDot operates on 5V USB-C power and connects to your network via Wi-Fi 2.4 GHz. Integration with Home Assistant occurs via the ESPHome native API; MQTT is a second option for those who prefer a broker-based setup. The AirDot also works completely standalone without Wi-Fi: measurement, display, pages, and history views remain active. The packaging includes a USB-C cable in the same color as the housing—white for the white variant and black for the black variant.

What the AirDot Measures

The measurement is performed by the Sensirion SEN66, an industrial combination sensor that combines CO₂, particulate matter, VOC, NOx, temperature, and humidity in a single module. For accurate CO₂ measurement, the AirDot also includes a separate SPA06 barometric pressure sensor, allowing the firmware to automatically compensate the SEN66 for ambient pressure. After startup, a warm-up time of 120 seconds is required before the values stabilize.

• CO₂ in ppm via NDIR measurement (Sensirion SEN66)
• Particulate matter PM1, PM2.5, PM4, and PM10 in µg/m³
• VOC Index and NOx Index (normalized 1–500)
• Temperature in °C and relative humidity in %
• Air pressure in hPa via SPA06 (also published as an entity in Home Assistant)
• Light intensity in lux (white variant only)

The Display

The round 480x480 color display shows multiple pages, which you can switch between using the physical button. The air quality summary classifies the current air quality based on a customizable profile (WHO, EPA, UK DAQI, India NAQI, China AQI, or Australia NSW) and provides immediate action advice. Each sensor value has its own log, allowing you to see trends over time. When a value reaches a critical level, the display can automatically switch to the history page of the sensor with the highest risk.

• Air quality summary with status level and advice
• Time and outdoor weather (with active Wi-Fi and location configuration)
• Flight Radar: nearby aircraft on a radar display; military traffic in orange
• Logbook per sensor value: PM1, PM2.5, PM4, PM10, CO₂, VOC, NOx, temperature, humidity, pressure, and light

⚠️ The light sensor and automatic brightness control are exclusively available on the white AirDot. For the black variant, the lux value is always 0 lx, and automatic brightness is not available.

Expansion and Accessories

The AirDot is a strong addition to other sensors in your smart home. Connect it to a motion sensor to activate ventilation only when the room is occupied, or combine it with a smart plug for direct control of a fan or air purifier. View all Sensy-One products for additional sensors from the same brand.

Safety and Reliability

The firmware runs on ESP-IDF, Espressif's stable framework, and supports OTA updates via the local setup portal without requiring a computer. Since the AirDot operates entirely locally, there is no dependence on external servers. In case of internet outage, measurement, display, and Home Assistant integration remain active.

Home Assistant

The AirDot integrates directly into Home Assistant via ESPHome. With HA discovery enabled, the device is automatically recognized once it's connected to the same Wi-Fi network. Local operation via the ESPHome native API is confirmed; a cloud connection is not required.

Step-by-step Pairing

• Connect the AirDot via USB-C (5V power)
• On first startup: select the language via the button, confirm with a long press
• Connect your phone or laptop to the AirDot's Wi-Fi network (name: airdot-xxxxxx)
• Open a browser and go to http://192.168.4.1 — this page is only accessible via the AirDot's own Wi-Fi network, not via your home network
• Choose your 2.4 GHz Wi-Fi network, enter the password, and save
• Enable Home Assistant discovery via the setup portal and save other settings
• Open Home Assistant > Settings > Devices & Services; the AirDot will automatically appear as an ESPHome device
• Click Configure and confirm

Do you want to adjust settings later, such as CO₂ calibration or a temperature offset? Go back to the AirDot's Wi-Fi network (airdot-xxxxxx) and open http://192.168.4.1 in your browser. The setup portal is always accessible via the device's own Wi-Fi network, even if the AirDot is already connected to your home network. For CO₂ calibration, take the AirDot outside, connect your phone to the airdot network, and perform the calibration via the setup portal.

Entities After Pairing

• Light in lux (white variant only)
• Pressure in hPa (SPA06)
• PM1, PM2.5, PM4, and PM10 in µg/m³
• Temperature in °C
• Humidity in %
• VOC Index
• NOx Index
• CO₂ in ppm

The publication interval is 10 seconds by default and can be adjusted to 5, 10, or 30 seconds via the setup portal. The AirDot also offers ESPHome API actions for display notifications from Home Assistant: via the show_display_alert action, you can send a title, message, display duration, and optional sound to the display.

MQTT

MQTT can be enabled via the setup portal. Configurable options include: broker address, port, username, password, topic prefix, and publication interval. MQTT discovery is built into the firmware. The default topic prefix is airdot.

Homey

The AirDot works via Wi-Fi and ESPHome. Homey Bridge and Homey Pro do not natively support ESPHome devices. Use the AirDot primarily with Home Assistant. Integration via MQTT is technically possible but requires additional configuration.

Other Platforms

• Home Assistant: fully supported via ESPHome native API, local, no cloud
• MQTT: configurable via setup portal, discovery built-in
• Homey, Google Home, Amazon Alexa, Apple Home: not supported

Automation Examples

Example 1 – Ventilation with High CO₂ (Simple)

• Trigger: CO₂ sensor rises above 1000 ppm
• Condition: time between 07:00 and 23:00
• Action: switch on a smart plug with a fan
• Second trigger: CO₂ drops below 800 ppm, fan off

Example 2 – Bedroom Warning with AirDot Display Notification (Advanced)

• Trigger: VOC Index > 150 and CO₂ > 1200 ppm simultaneously
• Condition: time 22:00–07:00 and bedroom presence sensor active
• Action 1: call ESPHome action show_display_alert with title "Air Quality", message "Open a window", duration_seconds 60, sound_enabled true
• Action 2: send push notification via HA Companion App: "Bedroom air quality poor, open a window"
• Action 3: repeat every 30 minutes as long as values remain elevated via repeat until

Points of Attention

• Requires 2.4 GHz Wi-Fi; 5 GHz is not supported by the ESP32 platform
• Operates exclusively on USB-C power, no battery option
• After startup, a warm-up time of 120 seconds is required before measurement values stabilize
• Light sensor and automatic brightness are exclusively available on the white variant
• For the black variant, the lux value is always 0 lx
• Not compatible with Homey, Google Home, Alexa, or Apple Home without modifications
• Placement near heat sources, direct drafts, or cooking steam affects temperature measurement
• Weather data and Flight Radar require an internet connection; local air quality measurement also works without it

Contents of the Box

• 1x Sensy-One AirDot (white or black, as chosen)
• 1x USB-C cable in the same color as the housing

Compatibility

Home Assistant via ESPHome | MQTT | Standalone use without network or Wi-Fi

Specifications

Frequently Asked Questions

How do I connect the AirDot to Home Assistant?

Connect the AirDot via USB-C. On first startup, select the language using the button on the device and confirm with a long press. Connect your phone or laptop to the AirDot's Wi-Fi network (name: airdot-xxxxxx) and open a browser at http://192.168.4.1. Enter your 2.4 GHz Wi-Fi details, enable Home Assistant discovery, and save. The AirDot will then automatically appear as an ESPHome device under Settings > Devices & Services in Home Assistant.

Do I need a hub or gateway?

No. The AirDot connects directly to your network via Wi-Fi and communicates with Home Assistant via the ESPHome native API. No Zigbee coordinator, Z-Wave stick, or other hub is required.

Does the AirDot also work without Wi-Fi?

Yes. The AirDot works completely standalone without Wi-Fi. Measurement, display, all pages, and history views remain active. Functions requiring an internet connection (Home Assistant, MQTT, time synchronization, weather data, and Flight Radar) will not be available. You can set up Wi-Fi later via the setup portal.

What is the difference between the white and black AirDot?

The white AirDot features a functional light sensor (lux) and automatic brightness control based on ambient light. For the black AirDot, the light sensor is not active: the lux value is always 0 lx, and automatic brightness is not available. All other functions are identical.

Is the USB-C cable included and in what color?

Yes, a USB-C cable is always included in the box. The color of the cable matches the housing: white for the white AirDot and black for the black AirDot.

Is the AirDot compatible with Homey?

Homey Bridge and Homey Pro do not natively support ESPHome devices. The AirDot is primarily intended for use with Home Assistant. Integration via MQTT is technically possible but requires additional configuration and is not out-of-the-box.

How do I set the correct air quality standard?

Via the local setup portal at http://192.168.4.1, you can choose an air quality profile that suits your region or preference: WHO/EEA Strict, Europe EEA, US EPA 2024, UK DAQI 5, India NAQI 5, China CN AQI 5, or Australia NSW 1H. The selected profile determines the status classification and action advice on the display. Also check out our other sensors for a complete air quality overview per room.

How do I open the settings if the AirDot is already paired?

The setup portal at http://192.168.4.1 is only accessible via the AirDot's own Wi-Fi network, not via your home network. If the AirDot is already configured and connected, go to your phone or laptop's Wi-Fi settings, manually connect to the airdot-xxxxxx network, and then open http://192.168.4.1 in your browser. This is also how you perform CO₂ calibration: take the AirDot outside, connect your phone to the airdot network, and start the calibration via the setup portal under Sensor Calibration.

✓ slimhuisje.nl delivers the AirDot in white and black, directly from stock. Fully local, no subscription, no cloud. Running into issues during Home Assistant configuration? Our customer service will help you right away.