Enhancement: add support for DFRobot SEN0467 (H2S) sensor

[21cncstudio]

Summary

Track future evaluation and possible support for the DFRobot SEN0467 hydrogen sulfide sensor (H2S, 0-100 ppm).

Aura currently supports the DFRobot SEN0466 for CO. SEN0467 is not a drop-in replacement for SEN0466, 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://wiki.dfrobot.com/sku_sen0465tosen0476_gravity_gas_sensor_calibrated_i2c_uart

Background

A previous discussion started in #85, but that thread was a support question rather than a properly-scoped feature request. This issue is meant to track the enhancement cleanly.

Proposed scope

• Detect and initialize SEN0467 without affecting existing SEN0466 behavior.
• Read and validate H2S concentration correctly.
• Expose the value through MQTT / Home Assistant discovery.
• Decide how H2S 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 SEN0467 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 H2S readings

If you own a SEN0467 and are willing to test pre-release firmware, please comment here.

Notes

This is a future enhancement request, not a bug in the current SEN0466 CO support.
No ETA yet.

[21cncstudio]

Update: DFRobot SEN0467 (H2S) 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 SEN0467.
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 H2S readings look reasonable
• MQTT / Home Assistant behavior
• exact SEN0467 module used

Please share results here if you try it.

[RDols]

I compiled and uploaded from the main branch (beta link in o3 issue is not working). It is detected and running.

[21cncstudio]

To understand more than just initial detection, I would need a boot log and a bit more detail about how it behaves after startup.