Control other devices - FengtianGu/Sonoff-Tasmota GitHub Wiki
Double press & hold
It is possible to control another device from remote by using following options:
From version 5.1.6 on, hold button functionality for both the push button AND the external push button was implemented.
If a ButtonTopic (and if SetOption1 (=ButtonRestrict) is ON) or SwitchTopic (and SwitchMode = 5 or 6) has been defined and a button is pressed longer than define KEY_HOLD_TIME (default 4 seconds) a MQTT message like cmnd/%topic%/POWER HOLD will be sent. HOLD message can be changed with command StateText4.
Command SetOption11 ON / OFF allows for swapping the functionality of the push button.
These changes result in the following table (larger image):
Example
You can control a ceiling fan from a Sonoff Touch:
If your standard topic of Sonoff Touch is light and the ceiling fan topic is ceilingfan issue these commands on the Sonoff Touch to activate the double press feature.
buttontopic ceilingfan
setoption11 1
Taken from the discussion: https://github.com/arendst/Sonoff-Tasmota/issues/200#issuecomment-343756826