Enhancement: add support for DFRobot SEN0469 (NH3) sensor

[21cncstudio]

Summary

Track future evaluation and possible support for the DFRobot SEN0469 ammonia sensor (NH3, 0-100 ppm).

Aura currently supports the DFRobot SEN0466 for CO. SEN0469 is a different gas target, but it belongs to the same DFRobot calibrated electrochemical I2C/UART sensor family, so it is a reasonable future extension to evaluate.

Official family reference from DFRobot:
https://www.dfrobot.com/product-2513.html

Proposed scope

• Detect and initialize SEN0469 cleanly without affecting existing supported sensors.
• Read and validate NH3 concentration correctly.
• Expose the value through MQTT / Home Assistant discovery.
• Decide how NH3 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 SEN0469 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 NH3 readings

If you own a SEN0469 and are willing to test pre-release firmware, please comment here.

Notes

This is a future enhancement request.
No ETA yet.

[mangermade]

I would like to test the NH3 sensor. I mentioned support for NH3 on Maker World last week. I'll order the sensor and have ready to test when you are. Thanks for the consideration.

[21cncstudio]

Update: DFRobot SEN0469 (NH3) 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 SEN0469.
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 NH3 readings look reasonable
• MQTT / Home Assistant behavior
• exact SEN0469 module used

Please share results here if you try it.

[JGKPelleas]

Hi Volodymyr, Thank you for all the great work, and great care put toward the device - FYI - tossing my hat in the ring to test the SEN0469 (and the SEN0467).

[21cncstudio]

Hi Volodymyr, Thank you for all the great work, and great care put toward the device - FYI - tossing my hat in the ring to test the SEN0469 (and the SEN0467).

That is great, thank you.

Please share as much detail as possible once you are ready — especially a boot log, detection behavior, restart behavior, warmup behavior, and whether the readings look reasonable.

[mangermade]

I installed the new firmware and the NH3 sensor was recognized and warmed up. I have a current reading of zero. I will next take it one of our processing plant engine rooms where our NH3 compressors are at. I should be able to compare the AURA numbers to what our refrigeration system is reading.

[21cncstudio]

Great, thanks for testing.

Please let the NH3 sensor run for at least 24 hours before comparing the readings. These electrochemical gas sensors need some time to stabilize after power-up, especially if they were just connected or moved.

After that, comparing Aura against the refrigeration system reading would be very useful.

[mangermade]

I wanted to see if you can add trending for the NH3 sensor as well as have that value display on the web interface.

[21cncstudio]

Yes, I will definitely add NH3 trending and Web UI display in the next update.

Did you get a chance to test the sensor further? Is everything working well after warmup?

[mangermade]

I haven't had a chance to test it. I don't think I will get much useful information without the trending.