Sonoff BASICR4 Wi-Fi Relay Module

Sonoff Basic R4 is a smart relay switch, a new version of Sonoff Basic R2, the basic member of the Sonoff range of internet-controlled relay switches. As a new feature, it is also compatible with Sonoff eWeLink-Remote remote controls (Sonoff S-MATE / S-MATE2 modules, R5 wireless switch).

It is a WiFi and Bluetooth-enabled relay switch that requires 230V AC power and is used to switch on/off electrical devices. Using an app on an iOS (Apple) or Android smartphone connected to the internet, you can remotely control the switch and set the on/off schedule.

Of course, there is also a physical push button on the relay. Remote access via mobile app can be shared with family members. Ideal for smart control of household electrical appliances that don't need constant operation but need to be switched on/off from time to time (e.g. aquarium circulator or aerator). You can conveniently switch on devices remotely before you get home, and you can also set a timer to switch off to save energy and money.

Sonoff Basic R4 does not have an input for an external thermometer or humidity sensor, so it is not possible to connect a wired sensor.
If you need to control temperature or humidity, choose the Sonoff TH relay series instead. 

Product features:

Mobile app - Free iOS and Android app: eWeLink
Checking the status - The mobile app shows the current status of the relay (on or off)
Compatible with eWeLink-Remote (Bluetooth) - Built-in Bluetooth receiver and hub function allow the S-MATE / S-MATE R3 modules and the R5 wireless switch to be used as local remote controls
Remote on/off - Wherever you are, you can remotely switch the relay (and the devices connected to it) on or off via the mobile app and the web.
Timer - Several timer functions are available: set time, recurring times, countdown/stopwatch, cycle.
Automatic switch-off - You can set the socket to switch off automatically after a set time after each switch-on
Pulse switch - The relay can also be set to a pulse switch, i.e. switching on for a short time (e.g. typically 0.5 or 1 second)
Possibility to share with others - Give access to the remote control e.g. to family members or other people
Groups and rooms - Organise your Sonoff and SmartWise smart devices into groups and rooms within the eWeLink app
Smart Management (Scene) - The SmartControl/Scene function in the eWeLink app allows the creation of conditional controls between different Sonoff/SmartWise devices. For example, you can turn on a Sonoff S26 outlet based on temperature or humidity data from a TH10 relay, or turn on a Sonoff or SmartWise smart switch based on an RF motion signal from a Sonoff RF Bridge gateway, or synchronize the on/off of two WiFi devices (e.g. a Sonoff light switch can turn on a Sonoff WiFi smart connector via WiFi).
Compatibility - Connectivity to Amazon Alexa, Google Assistant and Google Nest for voice control
Sonoff and its sister brand SmartWise are compatible with each other, both using the factory eWeLink app.