Air Sensor "Project AURA" - Electronic Parts Kit

Probably the best sensor in the world

Project Aura isn't just "another sensor" but a professional air quality station you build yourself: high-end sensors, large touchscreen, local data processing, Home Assistant integration – no soldering required. One evening to build, years of making better decisions about ventilation, heating, cooking, renovating, and sleeping.

Complete project description & original documentation (MakerWorld)

Variants

• "Basic" Variant (without formaldehyde sensor): All functions and sensors except formaldehyde. Instead, the AQI is displayed in the UI.
• "Plus" Variant (with formaldehyde sensor): Additionally with Sensirion SFA40 (HCHO) for renovation, new carpets, new furniture, "new car smell" & VOC/formaldehyde issues.
  

What Aura can measure

• Particulate matter: PM1, PM2.5, PM4, PM10 (from smoke to pollen/mold spores/dust)
• CO2: "Zombie effect"/concentration & ventilation needs
• VOC: volatile chemicals from furniture, cleaners, adhesives, etc.
• NOx: relevant for gas stoves/traffic/exhaust fumes, among others
• Temperature & humidity: dry heating air, comfort, susceptibility to infection
• Air pressure + trend: Delta over 3h and 24h (weather sensitivity/trend warning)
• Formaldehyde (Plus only): HCHO via Sensirion SFA40

Touchscreen Interface

• 4.3" IPS Touch (800×480): bright, wide viewing angle, 16 MB Flash
• Main Dashboard: large values (e.g., PM2.5, CO2, temperature, humidity) + color coding
• On-device settings: no PC required – directly via touch
• 12 Themes + Custom Theme Editor
• WLAN Screen: scan & connect to networks directly on the display
• MQTT Screen: broker/port/login/password + live status
• Auto-Night-Mode: dark colors according to schedule
• Auto-Screen-Timeout: 30s / 1m / 5m – wake up via touch
• Time/Date: RTC buffering + timezone + regular syncs with WLAN

Home Assistant Integration

• MQTT Auto-Discovery: appears in Home Assistant immediately after power-on
• 20+ Entities: sensors, switches, buttons (project-dependent)
• Local Operation: no unnecessary cloud dependencies; also works autonomously without internet
• Cross-Tech Integration: Via Home Assistant, you can combine Aura data with devices from other technologies (e.g., Zigbee, Z-Wave, Thread/Matter, WLAN) and build automations.

Assembly & Commissioning

• No-Solder Design: 0% soldering – plug connectors, cables, terminals
• One-Click Web Installer: connect board via USB, open installer, "Install"
• Small nuance: swap pins on one connector (1 minute, shown in instructions)

Scope of delivery (Electronic Parts Kit)

Included: all electronic parts according to the BOM list for the Basic version (without optional sensors), the PLUS variant additionally includes the formaldehyde sensor. Includes capacitor, battery, and screws.
Not included: 3D-printed enclosure, USB cable.

Core Hardware

• 1× Waveshare ESP32-S3-Touch-LCD-4.3 (ESP32-S3 Dual-Core, 16MB Flash, 4.3" IPS 800×480, capacitive touch)
• 1× Sensirion SEN66 (All-in-One sensor: PM1/2.5/4/10, CO2, VOC, NOx, temperature, humidity)
• 1× Adafruit SEN6x Breakout (Adapter/Breakout for SEN66)

Optional (Plus variant only)

• 1× DFROBOT Gravity – SFA40 (Formaldehyde/HCHO sensor based on Sensirion SFA40)

Barometer/RTC/I2C

• 1× Barometer and Temperature Sensor (Adafruit BMP580)
• 1× RTC Time Module (Adafruit PCF8523)
• 1× I2C Hub (Adafruit Qwiic / Stemma QT 5-Port Hub)
• 1× CR1220 (3V coin cell for RTC clock)

Power & Connection

• 1× Aluminum Electrolytic Capacitor (radial, 10V 470µF, 105°C) for power supply stabilization
• 1× Seeed Grove – Screw Terminal (screw terminal for power/capacitor, no soldering)
• 3× Grove → STEMMA QT/Qwiic/JST-SH Cable (100mm)
• 3× Qwiic/STEMMA QT compatible JST-SH 4-Pin Cable (50mm)
• 1× JST GH 1.25mm 6-Pin Cable (100mm)

Mounting

• NEW: Now 30× Screws (M2.5×6) with Torx T8

What else you need

• 3D-printed enclosure (Files/instructions via MakerWorld)
• USB cable + 5V power supply (stable supply recommended)
• WLAN (2.4 GHz) for network operation
• For Home Assistant: MQTT Broker (e.g., Mosquitto) and a running HA system

Complete documentation & project page:

MakerWorld: Project Aura – Make the Invisible Visible