Enhancement: add support for DFRobot SEN0471 (NO2) sensor

[21cncstudio]

Summary

Track future evaluation and possible support for the DFRobot SEN0471 nitrogen dioxide sensor (NO2, 0-20 ppm).

Aura currently supports the DFRobot SEN0466 for CO and is expanding support for related DFRobot calibrated electrochemical I2C/UART gas sensors. SEN0471 belongs to the same sensor family, so it is a reasonable future extension to evaluate.

Official reference from DFRobot:
https://www.dfrobot.com/product-2515.html

Proposed scope

• Detect and initialize SEN0471 cleanly without affecting existing supported sensors.
• Read and validate NO2 concentration correctly.
• Expose the value through MQTT / Home Assistant discovery.
• Decide how NO2 should appear in the local UI and web dashboard.
• Handle warmup, unavailable, and sensor-fault states cleanly.
• Document supported wiring, units, range, and limitations.
• Add tests where practical for shared protocol/parsing logic.

Testers wanted

I need testers with real SEN0471 hardware to help validate this once prototype support exists.

Useful tester feedback would include:

• detection and startup behavior
• warmup timing and stability
• expected units / scaling
• disconnect and reconnect behavior
• MQTT / Home Assistant output validation
• any real-world sanity checks for NO2 readings

If you own a SEN0471 and are willing to test pre-release firmware, please comment here.

Notes

This is a future enhancement request.
No ETA yet.

[RDols]

I do not have the one of the DFRobot Gravity sensors you proposed, but i do have the SEN0467 H2S Sensor.

https://www.dfrobot.com/product-2511.html

Is it possible to implement more generic DFRobot Gravity support? They use the same interface PCB, I2C commands are the same. Query what sensor is installed on the interface PCB, also the possibility to check and use all 4 addresses with different sensors.

Regards,
Richard

[21cncstudio]

I do not have the one of the DFRobot Gravity sensors you proposed, but i do have the SEN0467 H2S Sensor.

https://www.dfrobot.com/product-2511.html

Is it possible to implement more generic DFRobot Gravity support? They use the same interface PCB, I2C commands are the same. Query what sensor is installed on the interface PCB, also the possibility to check and use all 4 addresses with different sensors.

Regards, Richard

#91

[21cncstudio]

Update: DFRobot SEN0471 (NO2) support is now included in the official Aura v1.1.4 release.

Please use the stable 1.1.4 OTA build instead of the old beta binary:
https://github.com/21cncstudio/project_aura/releases/download/v1.1.4/project_aura_1.1.4_ota_firmware.bin

Please use I2C address 0x75 for SEN0471.
https://wiki.dfrobot.com/sen0465/docs/21907

If you test it, useful feedback would be:

• detected or not detected
• boot behavior after several restarts
• warmup behavior
• whether NO2 readings look reasonable
• MQTT / Home Assistant behavior
• exact SEN0471 module used

Please share results here if you try it.