What are the new trigger modes for MINI’s external switch? – Edge Mode

Edge mode, one of three new trigger modes, is intended for making the load state change on each press of switch button without having to check the on/off state from the switch button.


First off, an important question is here for you – Do you know what’s the foremost feature in SONOFF MINI? It’s OK whatever this is clear to you or not. The typically outstanding feature of MINI smart switch is the S1 and S2 interface are engineered for an external light switch connection as one more way to control MINI relay ON and OFF.

Like other switches, MINI allows you to connect a rocker light switch (without bouncing between On and Off positions) to realize the purpose of controlling the same light from two locations, like turning on the stair light downstairs and turning off it upstairs. Differently, connecting a light to MINI and you can enable the remote control with a mobile app, getting it on or off anywhere, anytime. Besides the app remote control, MINI can work with a smart voice assistant like Alexa and Google Home, which provides the possibility to access a hands-free voice control of the light, simpler to manage your home in the manner of smart control.

MINIR2 and MINIR4 both have this mode.

In the MINI circuit, the S1 is at signal ground level while the S2 is hanging with a pull-up resistor at 3.3V level. The change of the external switch state triggers the S2 signal level change. when S1 and S2 are disconnected (external switch state is open), the S2 signal level is still kept as 3.3V high level signal, the connection of S1 and S2 would lead S2 signal level into “ground” low. Here is a table to indicate the relationship of external switch state vs signal level.


This time, MINI comes a new improvement based on the previous external switch connection, which covers 3 external trigger modes:

MINIR2 and MINIR4 both have this mode.

What is the Edge Mode

Before we dive into the edge mode, let’s learn about the electronic term: signal edge detection. This refers to a technique widely used in embedded software and electronics. A signal edge is defined as the transition of the signal from a high state to a low state or from a low state to a high state as the above signal level table shows.

From this table, a falling edge would be observed for the state change of “Open to Closed”. Similarly, a rising edge occurs when the switch state is from “Closed to Open”. In this mode, either falling edge (switch contact from open to closed) or rising edge (switch contact from closed to open) is the trigger signal for MINI relay state change.


In the edge mode, the load of MINI reacts for every switch operation no matter if the external switch turns “On” or “Off”, that is the switch is flipped for continuous “On” or “Off after being pressed every time. 


MINI is a versatile device that can be easily connected to different types of switches, including self-locking switches and single-pole double-throw switches. When used with two-way control switches, MINI can be configured to operate in Edge Mode, which allows for two-way control of lighting systems.

In Edge Mode, MINI is able to toggle the state of its relay when triggered by a switch, making it an ideal choice for controlling the on/off state of lights. This feature makes it easy to control lighting systems from multiple locations using two-way control switches.