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The Serin Link on a bedside table beside a set of keys and a stack of books: a round black dial in a flared orange base, its face reading 72 degrees with Heating above it and the room at 70 degrees and 44 percent humidity below
A render of the Serin Link seen from the front and slightly to one side: a round black dial tilted back in a wide, flared orange base, its face reading 72 degrees with Heating above it and the room at 70 degrees and 44 percent humidity below
A render of the Serin Link head-on, the round face filling the frame: 72 degrees in large type with Heating above it, the room at 70 degrees and 44 percent humidity below, and the target arc drawn on the rim
A render of the Serin Link from the left: the dial tilted back at 45 degrees on a wedge-shaped orange base, with two sensor slots cut into the side of the base
A render of the Serin Link from behind: the back of the orange base with a USB-C port low in the middle of it, the sensor vents on the far edge, and the black rim of the dial rising behind
A render of the Serin Link with the body in black, so the body and the dial match
A render of the Serin Link with the body in off-white

Serin Link · Rotary knob display In development

Control your mini split without a phone.

The Serin Link is a rotary knob display for mini splits and ducted air handlers. Set the temperature, mode, and fan speed by turning the knob. It connects to the controller at your indoor unit and works from a desk, shelf, or nightstand.

The first production run is being built now. Send a message and we will tell you the moment ordering opens.

Reserve yours
Free US shipping No cloud, no account USB-C powered

What it needs to work ↓

The interface

Everyday controls, one knob.

Turn the knob to change the target temperature; the arc on the rim follows it. Press the knob to open the menu, or tap and swipe the touchscreen. The Serin Link only shows the modes and fan speeds your unit actually supports.

Every loop is recorded from the firmware's own simulator, which compiles the shipped UI source.

The Serin Link home face in Heating: the knob raises the target from 72 to 75 degrees and back
The Serin Link menu: a ring of shortcuts, the highlight stepping from one to the next
The menu: turn to highlight, press to open
The Serin Link airflow screen: fan speed dragged, then the vane stepped through its positions
Airflow: fan speed, then the vanes
The Serin Link mode picker: heat, cool, auto, dry, fan and off around the ring
Modes: only the ones your unit supports
The Serin Link zone picker: three rooms around the ring, the knob moving the selection
Zones: turn to a room, press to switch
The Serin Link glance face: just the room temperature, dim on black
At night: a dim number, not a glowing disc

Onboard sensor

Measures the temperature where you sit.

The base contains a Sensirion SHT41 temperature and humidity sensor, thermally calibrated against reference sensors. A paired Serin Link can serve as the controller's room temperature source, so the heat pump responds to the temperature at your desk or bedside instead of the air at the ceiling.

The reading travels straight to the controller, so it does not depend on your home Wi-Fi, a hub, or an automation. If your router or hub goes down, the heat pump continues to receive the room temperature.

How it fits

Works with the controller at your heat pump.

The Serin Link requires a Serin Controller installed at each indoor unit, or an ESP32 climate device running ESPHome with the serin_link component added. The controller manages the heat pump; the Serin Link displays its state and sends changes.

For Home Assistant

Works with your ESPHome devices.

Add the serin_link component to any ESP32 climate device with a few lines of YAML. The YAML generator writes them for you. Everything on the left lands in Home Assistant as the entities on the right. The protocol and the controller-side component are open source (Apache-2.0) on GitHub.

climate.yaml ESPHome 
serin_link:
  climate_id: hvac
  pair_button:
  link_sensor:
  screen:
Bedroom Home Assistant
Serin Link Temperature71.6 °F
Serin Link Humidity44 %
Screen
Primary Serin LinkBedroom ▾
Pair Serin LinkPRESS

Tech specs

The hardware inside.

Display 1.5″ round AMOLED · 310 ppi · capacitive touch
Controls Rotary dial with press · tap, drag, swipe, hold
Wireless ESP32-S3 · dedicated radio link straight to the controller
Sensor Sensirion SHT41 temperature + humidity, thermally calibrated · optional CO2
Power USB-C · no battery
Rooms Up to 7 per Serin Link · up to 4 Serin Links per controller

Dimensions and weight are published when the production run is final.

Good to know

Frequently asked questions.

Does it need Wi-Fi?

Not for everyday use. The Serin Link and the controller communicate over their own encrypted link. Your home Wi-Fi is used by the controller for updates and remote features, and the Serin Link can help set that up or repair it.

What does it need at the heat pump?

A Serin Controller at each indoor unit, or an ESPHome climate device running the serin_link component. The Serin Link does not talk to the heat pump directly.

Is it a thermostat?

No. The controller owns the control loop and is the source of truth; the Serin Link shows its state and sends changes. Set the temperature from the Serin Link or from your home app, and they all show the same number.

How do I switch between rooms?

Swipe on the home face to switch rooms, or hold to open the zone picker.

Does it stay lit at night?

Left alone, it fades to a glance face: a dim number in the dark, not a glowing disc. A setting replaces it with full display sleep. A dark dial only wakes on touch; it never changes a setting.

In development

Reserve one from the first production run.

The first production run is in progress. Send a note and we will email you when ordering opens.

In the box: the Serin Link, a USB-C cable, and a power brick. The body is 3D printed.

Reserve yours See the Serin Controller