RelayFi smart relay board review

By Rob Zwetsloot. Posted

ESP32 devices are a more traditional way to use IoT over a Wi-Fi network – in fact when Raspberry Pi Pico first came out, several add-on boards added Wi-Fi using it. Unlike Pico, RelayFi (£26/$31) is much more focussed towards home automation, while also in a fairly small package.

The four relays take up most of the board and handle conversion and control for four mains-powered devices. We highly suggest getting some kind of case for the board as there are solder points on the underside of the PCB. These relays are controlled via an optoisolator which does improve the safety of the relays and, despite there being four squeezed onto the board, the screw terminals have a decent amount of space between them. Still – caution is recommended with this, like any other relay.

Connecting to things

With a series of I2c and standard component pins, you can add a little extra control to the board that is all programmed using the classic Arduino IDE. As it’s all Wi-Fi connected, having it talk to a Raspberry Pi or Pico W is a matter of making sure it’s looking for the right thing. Like an Arduino board, a micro USB port is used to power and connect to it for programming, which also supports various smart home systems for voice control via RelayFi.

It’s a fairly solid build for such a relatively cheap board, and the ease of coding helps with its appeal as well.


7/10 A solid IoT board with easy programming functions that can interact with Raspberry Pi just fine.


Microcontroller: ESP32 Connectors: Relays × 4, 5 × 3 component pins, I2c breakout, USB micro data port Radio: Wi-Fi, Bluetooth 4.2, BLE

From The MagPi store


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