Switches

What are smart in-wall modules and how do they differ from touch wall switches?

A smart in-wall module is an electronic unit installed inside the back-box — behind an existing wall switch or directly in the distribution board. Unlike touch wall switches that replace the entire wall plate, a module preserves the original wall appearance and lets you continue using the physical switch alongside app control. This solution is popular during renovations and wherever the existing aesthetic must be maintained.

Smart modules control 230 V in a lighting or other electrical circuit. They communicate via WiFi or ZigBee with a mobile app, a voice assistant or a local hub. Features include time schedules, automation triggers and remote switching from anywhere in the world.

Communication protocols: WiFi, ZigBee and Matter

The choice of protocol is crucial for installation convenience and long-term reliability:

• WiFi — the module connects directly to the home router, no gateway needed. Sonoff Basic R2, Dual R3, POWR3 and 4CHR3 are popular WiFi models. Simple setup in the eWeLink app.
• ZigBee — lower power consumption, better stability with many devices. Requires a ZigBee gateway (e.g. Sonoff Zigbee Bridge or BlitzWolf BW-IS1). Models: Sonoff ZBMINIR2, ZBMINIL2, MINI-ZB2GS.
• Matter — the new open smart home integration standard. Sonoff MINIR4M supports Matter natively, giving full compatibility with Apple Home, Google Home, Amazon Alexa and SmartThings without separate protocol gateways.

Important installation note: neutral wire (N)

Most smart modules require three wires in the back-box: live (L), neutral (N) and load output. The issue is that in older electrical installations only the live wire runs to the switch back-box, while the neutral goes directly to the light fitting. In that case, opt for models designed to work without a neutral:

• Sonoff ZBMINIL2 — ZigBee, specifically for no-neutral installations (min. 3 W load)
• Sonoff MINIR4M — Matter, works without N wire with a suitable load
• BlitzWolf BW-SS1 — WiFi, can operate without neutral with LED bulbs

Before purchasing, check how many wires reach your back-box. If there are only two (L and load output), choose a no-neutral model or ask an electrician to add a neutral bypass.

Modules for blinds and shutters

Controlling electric blinds requires a two-channel module that alternately powers the motor up and down. Available dedicated models:

• Sonoff MINI-ZBRBS — ZigBee, specifically for blinds, with position detection
• Sonoff DUALR3 and DUALR3 Lite — WiFi, two channels, blind and shutter control, energy metering in the DUALR3 version
• BlitzWolf BW-SS12 — WiFi, dedicated blind controller with stop-at-any-position function
• Meross MSG200HK — garage door controller with Apple HomeKit

Before purchasing, check the voltage and type of the blind motor. Most models support 230 V AC motors, but verify with the specific module's technical specification.

Multi-channel modules and energy monitoring

Where you need to control several circuits from one back-box or distribution board, multi-channel models are ideal:

• Sonoff 4CHR3 — four independent WiFi channels in a single DIN enclosure, each up to 10 A
• Sonoff POWR3 — one WiFi channel up to 25 A with real-time energy metering, overload protection and kWh reports
• Sonoff Dual R3 — two channels with individual energy metering, up to 15 A total
• BlitzWolf BW-SS4 to BW-SS7 — single and multi-channel WiFi modules for various enclosures

Energy monitoring is particularly useful for high-consumption loads: air conditioners, boilers, electric heaters or machinery supply circuits.

Meross HomeKit: modules without cloud dependency

Meross MSS710HK and MSG200HK are Apple HomeKit-certified modules that operate locally via the router without Meross external servers. Control via the Home app on iPhone and iPad, integration with iOS automations, Siri voice control. For Apple users this is the only reliable path to full local integration — without the risk of losing functionality if a cloud service is discontinued.

Installation: when is an electrician necessary?

Replacing a standard switch with a smart module involves 230 V wiring. Always turn off the circuit breaker for the relevant circuit and verify zero voltage with a multimeter before working. If you are unsure about the wiring or it is an old installation, hire a qualified electrician.

Related smart home categories

Smart modules form a cohesive ecosystem with other devices. Also check: smart sockets for plug-in device control, touch wall switches as an aesthetic alternative, sensors for event-triggered automations and ZigBee gateways and hubs for building an extensive device network.

FAQ — Smart in-wall modules

Do I need a neutral wire to install a smart module?

Not always. Models such as Sonoff ZBMINIL2 or MINIR4M can work without a neutral wire by drawing minimal current through the load (a bulb or other device). A minimum load on the output is required — too low a LED bulb wattage may cause flickering. With no-neutral installations, use bulbs of at least 5–7 W or add an RC filter.

Which module to choose for blind control?

For 230 V AC electric blinds you need a module with two alternating channels. The easiest choice is Sonoff DUALR3 (WiFi, energy metering) or Sonoff MINI-ZBRBS (ZigBee, dedicated blind module with positioning). BlitzWolf BW-SS12 is a WiFi alternative with a stop-at-any-position function.

ZigBee module or WiFi?

WiFi is simpler to install (no gateway) and works immediately after setup in the eWeLink app. ZigBee requires a gateway but offers lower latency, better stability with many devices and the ability to operate locally without the internet. If you are planning a network of more than 10–15 smart home devices, ZigBee with Sonoff Zigbee Bridge or iHost is the better long-term choice.