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CN105 · ESP32 · 100% local

Smart control for Mitsubishi mini-splits

The Serin Controller is a pre-assembled CN105 ESP32 controller for Mitsubishi Electric mini-splits. It communicates directly with the heat pump, with no cloud account or subscription. Pre-assembled CN105 controller. Works with Home Assistant, Apple Home, Google Home, or Alexa. No cloud, no subscription.

Buy now from $35Check compatibility
The Serin Controller, a compact Wi-Fi controller board with the CN105-to-Grove cable attached

Control it from the app you already use

The same hardware supports five platforms. Pick yours to see its features and requirements.

Apple Home Home Assistant Google Home Alexa SmartThings
The Home Assistant thermostat card for the mini-split, cooling to 75.2 degrees with fan and swing controls Home Assistant
The Home app thermostat screen for the mini-split, set to cool to 76 degrees Apple Home
The Google Home thermostat screen for the mini-split, heating to 74 degrees with the room at 68 Google Home

From compatibility check to local control

  1. Confirm compatibility

    Enter your indoor-unit model number to check CN105 compatibility before ordering.

  2. Install the controller

    The guide covers board preparation, turning off HVAC power, and connecting the cable to CN105.

  3. Finish setup in your app

    Complete setup in Home Assistant, Apple Home, Google Home, or Alexa.

Check your model Read the quick start →

Controllers and accessories

The Serin Controller is available now. Serin Link and Multi-Zone Controller are in development.

Available now · from $35

Serin CN105 ESP32 Controller

Pre-assembled CN105 ESP32 controller for one Mitsubishi indoor unit. Compatible with Home Assistant, Apple Home, Google Home, or Alexa.

View controller →
In development

Serin Link

A bedside dial and temperature sensor for adjusting a mini-split without opening an app. Works with a Serin Controller or compatible ESPHome climate device.

Learn more →
In development

Multi-Zone Controller

Whole-system control from one device. Connects to a City Multi, P-series or branch-box M-series and brings every indoor unit into your smart home.

Learn more →

Why the CN105 port beats the alternatives

Mitsubishi's cloud adapter costs around $227 and needs a vendor account and the vendor's servers for setup, remote access, and schedules. IR blasters send commands blindly, with no feedback from the unit.

Serin Controller Cloud adapter IR blaster
Cost from $35 assembled · ~$18 DIY ~$227 ~$79–$139
Feedback Real-time, two-way Two-way, app only None at all
Works offline Yes, 100% local In-home control only Varies
Firmware Open source Proprietary Proprietary
Serin Controller
Cost
from $35 assembled · ~$18 DIY
Feedback
Real-time, two-way
Works offline
Yes, 100% local
Firmware
Open source
Cloud adapter
Cost
~$227
Feedback
Two-way, app only
Works offline
In-home control only
Firmware
Proprietary
IR blaster
Cost
~$79–$139
Feedback
None at all
Works offline
Varies
Firmware
Proprietary

From $35 · free US shipping

Bring your mini-split into your smart home

Each indoor unit needs one controller. Check your model number first. It takes ten seconds.

Buy now from $35 Check your model →