This is a sample implementation of the Huum sauna controller communication protocol. It is used to control your Huum sauna without relying on their proprietary cloud.

This repository is accompanied by a blog post.

• Bun
  • The project is using Bun 1.12.4

1. Install dependencies bun install
2. Start the server bun run start

The server starts a TCP server on port 6969. The port must not be changes. What can be changes is the host. To do so, set TCP_HOSTNAME to what you desire. It defaults to 0.0.0.0.

The TCP server is used to exchange messages with the sauna heater.

Another, HTTP, server is started on 0.0.0.0:8080. Both components can be changed with HTTP_HOSTNAME and HTTP_PORT. The endpoints on that server are used to enable controlling the sauna heater by more conventional methods (curl...).

GET /status Responds with a plain number of the current temperature reading.

POST /start Starts the heater with a target heating temperature

type TurnOnRequest = {
    targetTemperature: number;
    durationHours: number;
}

POST /stop Stops the heater.

type TurnOffRequest = {
  targetTemperature: number;
}

Message is sent by the server to set how often the sauna controller should report its temperature sensor reading and heater state. Can be used whenever to update the frequency.

Sample Message:

02 3f 31 2e 68 fc 00

Used by both the local physical interface and the server to turn the heater on and off.

Sample Message:

07 38 00 00 00 00 03 47 2f 2e 68 77 59 2e 68 47 2f 2e 68 ec c5 ef 10 00

Sample message for turning the heater off

07 38 00 00 00 00 03 00 00 00 00 00 00 00 00 65 42 2e 68 75 59 fc 10 00

The "heating started" and "heating stop" timestamps are here zeroed, meaning the heater will turn off.

Message is used to send heater state changes to the cloud.

Sample Message:

08 38 00 00 00 00 03 00 00 00 00 00 00 00 00 3f 31 2e 68 00 00 00 00 01 00

Update about heating being stopped follows the same logic as "Heater control"

Sent by the controller to report temperature sensor reading.

Sample Message:

09 21 00 fc 24 00 00 00 00 00 00

Sent by the controller when establishing connection with the cloud server. Contains firmware version, controller's friendly name, and some other stuff I'm too lazy to figure out.

Sample Message:

0b 00 00 ac 68 b5 9c 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 51 34 2d 34 2d 32 2e 32 2e 31 32 31 33 2d 34 61 31 64 36 64 61 31 2d 34 00 00 00 00 00 55 51 34 20 45 55 20 57 69 46 69 00 00 00 00