FAQ

Product & Variants

1. What is the difference between Basic and Complete?

The Complete version includes the SPS30 particulate matter sensor for measuring PM1, PM2.5, PM4, and PM10 (fine dust).

2. Can I upgrade from Basic to Complete?

The PM sensor module can be added later, but requires opening the device and some technical knowledge. Contact us via smarthomeshop.io/contact for upgrade options.

3. Is the UltimateSensor suitable for outdoor use?

No. The UltimateSensor is rated IP20 and designed for indoor use only. Exposure to rain, moisture, or extreme temperatures will damage the device and void the warranty.

Installation & Setup

4. How do I install the UltimateSensor?

1. Connect power via USB-C or PoE (Ethernet firmware required for PoE)
2. Connect to the WiFi hotspot ultimatesensor (password: ultimatesensor)
3. Select your home WiFi network in the captive portal
4. Home Assistant will auto-discover the device

👉 See the full Installation Guide

5. What's in the box?

• UltimateSensor device
• Optional: USB-C adapter set with a 3 meter cable (if selected at checkout)
• Optional: Wall mount (if selected at checkout)

6. Can I mount the UltimateSensor on the wall?

Yes! An optional wall mount is available. The device can also stand freely on a shelf or cabinet.

7. What's the ideal placement for the UltimateSensor?

• Height: 1-2 meters from the floor
• Location: Away from direct sunlight, heat sources, and air vents
• mmWave coverage: Point the front toward the area you want to monitor

⚠️ Direct sunlight can cause the casing to yellow and affect sensor accuracy.

Connectivity

8. How do I connect the UltimateSensor to WiFi?

When first powered on, the device creates a hotspot named ultimatesensor with password ultimatesensor. Connect to it and follow the captive portal instructions to select your WiFi network.

9. Why isn't the WiFi hotspot appearing?

• Wait 1-2 minutes after powering on
• The hotspot only appears if WiFi isn't configured
• Try a different device (phone vs laptop)
• If it was configured before, it only appears about 1 minute after the device fails to reach your WiFi

10. Can I use Ethernet instead of WiFi?

Yes! The UltimateSensor supports Ethernet with Power over Ethernet (PoE). You need the Ethernet firmware: choose Ethernet on the setup page, change UltimateSensor Firmware Variant in Home Assistant, or flash it via USB-C.

👉 See the Firmware Guide for instructions

11. What are the Ethernet requirements?

• DHCP enabled on your network
• Same VLAN as Home Assistant (or proper routing configured)
• No firewall blocking local communication
• PoE switch/injector for power-over-ethernet

12. Does the UltimateSensor require internet access?

No. With local firmware the UltimateSensor works 100% locally. The device only goes online for the firmware version check on GitHub Pages and for the time from an NTP server. All sensor data stays on your local network.

Sensors & Measurements

13. What does the UltimateSensor measure?

14. How accurate is the CO₂ sensor?

The SCD41 accuracy:

• 400-1,000 ppm: ±(50 ppm + 2.5% of reading)
• 1,001-2,000 ppm: ±(50 ppm + 3% of reading)
• 2,001-5,000 ppm: ±(40 ppm + 5% of reading)

15. Why do my sensor readings seem inaccurate?

• CO₂: Needs 24+ hours for initial calibration
• Temperature: May need offset adjustment due to internal heat
• All sensors: Avoid placement near heat sources or in direct sunlight

👉 See the Calibration Guide

16. How does the mmWave radar work?

The LD2450 radar can:

• Detect up to 3 people simultaneously
• Track position (X/Y coordinates), distance, speed, and angle
• Use up to 4 polygon zones with individual presence detection, plus 2 exclusion zones and 2 entry lines for people counting
• Detect through thin walls (may require zone adjustments)

17. What's the difference between PIR and mmWave?

Use PIR for quick motion triggers and mmWave for true occupancy detection.

18. Can I disable sensors I don't use?

Yes. In Home Assistant, go to the device and disable individual entities you don't need.

Home Assistant Integration

19. How do I integrate with Home Assistant?

The UltimateSensor should be auto-discovered by Home Assistant. If not:

1. Go to Settings → Devices & Services
2. Click "Add Integration"
3. Select "ESPHome"
4. Enter the device's IP address

20. What can I automate with the UltimateSensor?

• Turn on lights when someone enters a room
• Start ventilation when CO₂ exceeds a threshold
• Send alerts for poor air quality (VOC/PM)
• Adjust HVAC based on temperature/humidity
• Track room occupancy for energy savings

👉 See Usage Guide for automation examples

21. Is there a custom Home Assistant card?

Yes! We provide a custom dashboard card optimized for the UltimateSensor.

👉 See Home Assistant Integration

mmWave Zones

22. How do I configure detection zones?

Draw them in the Room Designer of the SmartHomeShop integration in Home Assistant. You get:

• 4 polygon zones with up to 20 points each
• 2 exclusion zones
• 2 entry lines for people counting

The zones are stored on the sensor. See the Calibration Guide.

23. Why is the mmWave detecting through walls?

mmWave radar can penetrate thin walls. Solutions:

• Shrink your polygon zones so they end at the wall
• Draw an exclusion zone over the area behind the wall
• Reposition the sensor

24. What does "Tracking Presence Timeout" mean?

This is the time the sensor waits before reporting "no occupancy" after the last detection, from 1 to 600 seconds. A longer timeout prevents flickering when someone is stationary.

Display & LED

25. What does the OLED display show?

The built-in display shows:

• CO₂ level (large, center)
• Temperature (top right)
• Humidity (middle right)
• Light/Lux (bottom right)
• PIR indicator (when motion detected)

26. Can I control the back LED?

Yes! The Back Light entity in Home Assistant lets you turn it on/off and change colors. It's a WS2812B RGB LED.

Firmware & Updates

27. How do I switch between WiFi and Ethernet firmware?

1. WiFi → Ethernet: Change UltimateSensor Firmware Variant in Home Assistant, or choose Ethernet on the setup page. The device installs the Ethernet firmware over WiFi
2. Ethernet → WiFi: Requires USB-C flashing

👉 See the Firmware Guide for detailed instructions

28. How do I update the firmware?

• OTA: Through the UltimateSensor Firmware update entity in Home Assistant, or through ESPHome Device Builder for an adopted device
• USB-C: Through the web flasher. Remove the LD2450 first, see the Firmware Guide

29. Where can I find the source code?

All ESPHome YAML configurations are available on GitHub: 👉 github.com/smarthomeshop/ultimatesensor

Power

30. What power supply do I need?

• USB-C: Any adapter providing at least 1A (5V)
• PoE: IEEE 802.3af compatible switch or injector

The optional USB-C adapter set works, or use any USB-C adapter you have.

31. Can I power via PoE?

Yes, but only with Ethernet firmware installed. PoE provides both power and network connectivity over a single cable.

Warranty & Support

32. What's covered under warranty?

The UltimateSensor has a 2-year warranty covering manufacturing defects and hardware failures. Not covered:

• Discoloration from sunlight
• Water/moisture damage
• Physical damage
• Modified firmware/hardware

👉 See Warranty and Support

33. How do I get support?

• Discord: smarthomeshop.io/discord, fastest response
• Contact form: smarthomeshop.io/contact

Note: We do not provide support via email for installation questions.