I bypass-wired a smart ceiling fan and documented the terminology mess that almost killed me
I wired a Tuya WiFi ceiling fan in bypass mode so the wall switch acts as a Zigbee event input instead of cutting power to the canopy.
The typical: "smart device needs constant power, wall switch keeps killing it" problem.
I don't know if you guys have found yourself in the same situation, but truth to be told...
The wiring itself is not the hard part.
The hard part was figuring out what to even search for!!
Because the same trick have a dozen names across HA forums, Zigbee2MQTT, Sonoff docs.... I was getting confused, I did not even know what I was reading...
So here a list of terminology I have found.
Hardware wiring choice:
- bypass wiring (HA community)
- decoupled switch wiring (Z2M's name for the same thing)
Firmware feature on the relay:
- detached relay mode (Sonoff)
- decoupled mode (Z2M)
- switch-only mode (Tasmota)
They can produce similar end behaviour but they are not the same thing.
...took me embarrassingly long to untangle.
So I wrote it all down.
Repo has diagrams, vendor PDFs, a parametrised HA automation, and a terminology table at the bottom of the README so the next person doesn't have to go through a similar situation:
https://github.com/agigante80/homeassistant-bypass-wiring-fan
The project is a Sonoff MINI-ZB2GS in a Spanish switch circuit, driving a Ovlaim DC ceiling fan, but the technique is brand-agnostic and the diagrams are editable Excalidraw.
PRs and feedback is more than welcome! :)