SONOFF MINI Extreme (MINIR4) ESP32 WiFi smart switch can fit into most gang boxes

SONOFF MINI Extreme (aka MINIR4) is a ridiculously small WiFi smart switch based on ESP32 wireless microcontroller and designed to be connected to a load such as a light bulb and a wall switch that can be a momentary switch, a door exit switch, an SPDT switch, a latching switch, or even dry contact sensors.

The tiny form factor (39.5×33 x16.8mm) enables the WiFi smart switch to fit into various boxes, even the smaller European gang boxes. Just like other SONOFF home automation devices, the MINIR4 works with eWelink mobile app, but it also implements some new interesting features such as the ‘Detach Relay’ mode.


SONOFF MINI Extreme (MINIR4) specifications:

  • MCU – Espressif Systems ESP32 dual-core wireless microcontroller
  • Connectivity
    • 2.4 GHz WiFi 4
    • Bluetooth LE used for pairing
  • Input – 100-240V ~ 50/60Hz 10A Max
  • Output – 100-240V ~ 50/60Hz 10A Max (resistive load)
  • Dimensions – 39.5 x 33 x 16.8mm
  • Casing material – PC V0
  • TÜV, CE, and FCC (ID: 2APN5MINIR4) certifications

SONOFF MINIR4 Wiring instructions

If it looks familiar, it’s because SONOFF introduced the ZBMINI Extreme with Zigbee connectivity at the end of last year, and the SONOFF MINI Extreme is about the same but with WiFi and Bluetooth LE, plus support for higher loads up to 10A.

Some highlights of the new switch include support for “detach relay” mode in which the states of external switches and relay are separated, so operating the external switch button won’t affect the relay state and eWeLink-Remote Control mode where the MINIR4 acts as a local gateway for the  R5 and S-MATE switches, so a light bulb can be controlled by multiple switches. The company also says it works with Google Home and Amazon Alexa voice assistant, as well as Home Assistant, eWelink Web, and IFTTT with the last two online available in the paid version (Advanced Plan) of the eWelink app.

SONOFF MINI Extreme MINIR4 WiFi Switch Unboxing
10 Baht coin for scale

While the SONOFF MINI Extreme has just been launched, I received one as part of a Christmas gift set last December, and I was asked not to write about it until the official announcement. I haven’t taken the time to test it yet, but I did open the device to check out the hardware design.

MINIR4 Teardown

As one would have imagined before opening the device, everything is really tight inside the device with the relay several capacitors, and other components leaving very little space. I was also surprised to see some thermal pads, but I suppose it may be required to cool down such a small device.

SONOFF ESP32 board

The ESP32 module is located on the side with a ceramic antenna (Blue) and a thermal pad covering the main components.

MINIR4 V1.0 board

The pins connected to the mains have extra solder as one would expect. SONOFF seems to have improved in terms of safety over the years, as in the past they always lacked safety certifications such as TUV or UL, but all their new products are TUV certified, although I could not find the exact certification used. They also have a feature called “delay power-on state” to add a user-defined delay to turn on devices which should be especially useful after a power failure where you may not want everything to turn on at the same time.

Since the MINIR4 has been received as a gift by multiple users last year, it already has a template in Tasmota and Digiblur tested it with both Tasmota and ESPHome. SONOFF is selling the MINI Extreme (MINIR4) for $9.90 with free shipping for orders over $89, and the R5 scene control or the S-MATE switch can be added for $12.49 and $7.49 respectively. Coupon code CNXSOFTSONOFF can shave 10% off the price as well.

Continue reading “SONOFF MINIR4 review – A Tiny WiFi Smart Switch tested with eWelink app/web, and R5 controller“.

Thanks to Paisit for the tip.

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11 Replies to “SONOFF MINI Extreme (MINIR4) ESP32 WiFi smart switch can fit into most gang boxes”

  1. It’s quite small indeed, and the idea to also support a physical switch is great, as often such “connected devices” tend to only work with their peers.

    1. First time I hear about “UKCA” – is that really something? But the post-brexit kingdom is indeed comedy gold at the highest level. Latest news going around the world is the limitation of salad per person and that brits should rather eat carrots.

  2. Interesting for the new enhancement over the predecessor. Such as working with S-Mate and leveraging ESP32. I am using lots of MiniR2 Wifi and it’s time to try MiniR4!

  3. I learned of this from cnx software. I have been wanting to control a lamp on a non switched outlet with another switch in the room. This device looks like the perfect half to a solution. . How can i do this with the device? I did not see wall plug units offered. Does this work with other wall plug devices?

    1. It’s supposed it fit into the gang box where your switch is located. But bear in mind you’ll need a neutral wire for the MINIR4. If you want to control it from another switch in the room then you’d need the R5 as well.

  4. All I can say is all my shelly 20 25 have died within 18 months and sonoffs are still going strong
    Love the hacker friendly shelly but angry wife dictates to stick to sonoff now

    1. I’m also finding early death of shelly devices an issue, sonoff for me from now on, still running some sonoff basics that are more than 5 years old.

  5. You received it 2 months ‘early’ so you could take the time to test it before reviewing, not just leave it sat in a box. What a waste of an article

  6. It will be nice if Sonoff mini can work with just live wire connection.(no need for the neutral wire) since we dont normal find neutral wires running into the switch gang box. There are similar devices in the market which works without the neutral wires. Other wise its a cool device as far the reviews and physical looks are concerned.

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