UltimateSensor Mini is a compact all-in-one ESPHome room sensor for Home Assistant. It measures air quality, occupancy, light, temperature, humidity, and optionally particulate matter, with fully local operation by default.
Product page: https://ultimatesensor.nl/en/mini
UltimateSensor Mini combines multiple room sensors on one ESP32-S3 device. The ESPHome firmware exposes the measurements directly to Home Assistant and supports local onboarding through captive portal, Improv BLE, and Improv Serial.
The Complete firmware adds SPS30 particulate matter sensing for PM measurements. The Basic firmware uses the same shared configuration without the particulate matter sensor.
- CO2 sensing with SCD41
- Temperature and humidity sensing
- Light sensing with BH1750
- VOC and NOx index sensing with SGP41
- LD2450 mmWave occupancy sensing
- Microphone, speaker, and Home Assistant Voice Assistant support
- RGB front and back lights
- WiFi onboarding with captive portal, Improv BLE, and Improv Serial
- Fully local operation with ESPHome and Home Assistant
- Optional SPS30 particulate matter sensing in the Complete variant
| Version | Chip | Connectivity | Description |
|---|---|---|---|
| V1 | ESP32-S3 | WiFi | UltimateSensor Mini hardware with Basic and Complete firmware variants |
We publish two customer-facing firmware variants for the V1 hardware.
| Hardware | Variant | Description |
|---|---|---|
| V1 (ESP32-S3) | Basic | Standard firmware without the SPS30 particulate matter sensor |
| V1 (ESP32-S3) | Complete | Full firmware with SPS30 particulate matter sensing |
| V1 (ESP32-S3) | Beta Basic | Experimental local wake word firmware without the SPS30 particulate matter sensor |
| V1 (ESP32-S3) | Beta Complete | Experimental local wake word firmware with SPS30 particulate matter sensing |
| Sensor | Description |
|---|---|
| CO2 | Room CO2 concentration |
| Temperature | Environment temperature |
| Humidity | Environment humidity |
| Light | Ambient light level |
| VOC Index | Volatile organic compound index |
| NOx Index | Nitrogen oxide index |
| Occupancy | mmWave occupancy detection |
| PM1.0 / PM2.5 / PM4.0 / PM10 | Particulate matter measurements in the Complete variant |
| WiFi Signal | WiFi signal strength |
| Uptime | Device uptime |
- Power the UltimateSensor Mini with USB-C.
- Flash the desired firmware with the web flasher or ESPHome CLI.
- If WiFi is not configured yet, connect to the fallback hotspot.
- Complete onboarding with captive portal, Improv BLE, or Improv Serial.
- Add the device to Home Assistant through the ESPHome integration.
Web flasher: https://smarthomeshop.io/firmware Product page: https://ultimatesensor.nl/en/mini
- Customer-facing release notes: CHANGELOG.md
- GitHub Releases: https://github.com/smarthomeshop/ultimatesensor-mini/releases
ultimatesensor-mini/
├── ultimatesensor-mini-v1/ # V1 ESPHome configurations
│ ├── ultimatesensor-mini-common.yaml
│ ├── ultimatesensor-mini-basic.yaml
│ ├── ultimatesensor-mini-complete.yaml
│ ├── beta-ultimatesensor-mini-common.yaml
│ ├── beta-ultimatesensor-mini-basic.yaml
│ ├── beta-ultimatesensor-mini-complete.yaml
│ └── default_16MB.csv
├── .github/workflows/ # Build and release automation
├── CHANGELOG.md # Customer-facing firmware notes
├── SECURITY.md
└── images/
Pre-built firmware manifests are published on the gh-pages branch.
- V1 Basic:
ultimatesensor-mini-basic-manifest.json - V1 Complete:
ultimatesensor-mini-complete-manifest.json - V1 Beta Basic:
beta-ultimatesensor-mini-basic-manifest.json - V1 Beta Complete:
beta-ultimatesensor-mini-complete-manifest.json
PRs and issues are welcome. Please keep changes modular and follow ESPHome best practices.
If a PR changes firmware behavior or release-visible functionality, add a customer-facing note to CHANGELOG.md under Unreleased.
- Product info and guides: https://ultimatesensor.nl/en/mini
- Store: https://smarthomeshop.io
- Community and support: https://smarthomeshop.io/discord
This project is released under the CC BY-NC 4.0 license. See license.