Sauna Controller

Abstract

1. Introduction

A fascinating and innovative project that implements a powerful sauna controller using ESPHome – smart, reliable, and highly impressive.

For about 60€, you get an awesome sauna controller!

The sauna controller is built from scratch with no additional components needed. Integration is done with Home Assistant, and the controller itself is built around the excellent ESPHome.

2. Objective

Sauna Controller with esp8266 ESPHome for a integration in Home Assistant

This project demonstrates how ESP8266 can be applied to a real-world Internet of Things (IoT) problem.

3. Key Features / Modules

• Real PID controller
• Power and energy calculation
• Customizable
• No cloud dependency
• Remote access
• Expandable
• Affordable
• Reliable
• Easy to build
• Easy to use

4. Technology Stack

• The brain of the Sauna Controller: A Wemos D1 ESP8266 or any other device running ESPHome.
• Thermal fuse: A crucial component. If something goes wrong and the heater overheats, the thermal fuse burns out and switches off the heater, cutting the voltage for the high current switches.
• High current/voltage switch to heat the sauna: I chose SSR relays like 3 SSR-40DA. SSR relays are wear-free and allow for easy PID controller implementation without noise.
• Optional additional sensors: I use various other sensors to measure temperature in the room, between the sauna wall and the room wall, and humidity.
• Sauna lamp: The controller also drives WS2812b LEDs for the sauna lamp, allowing for fun lighting effects.
• Junction box, cables, and other small components.

5. System Requirements

General requirements for this technology stack — check the README for exact versions.

• See the project README for exact requirements
• Git (to clone the repository)

6. Installation & Setup

git clone https://github.com/killee/Sauna-controller.git
cd Sauna-controller

1. Flash the firmware with ESPHome.
2. Connect your ESP8266/ESP32 device according to the pin mapping.
3. Follow the on-screen instructions from Home Assistant and adjust settings in the YAML files as needed.
4. Integrate the controller with Home Assistant for easy control.
5. Use the web interface to set target temperatures, view sensor status, and monitor energy consumption.
6. The minimal version (sauna_simpler.yaml) is great for a lean setup, while sauna_controller.yaml offers extra features if you want advanced functionality.

Full setup instructions are in the project README.

7. Future Enhancements

Suggested extensions you can add to make this your own project.

• Add a mobile dashboard using Blynk or Firebase
• Store readings in a cloud database for history charts
• Add alerts via SMS / Telegram when thresholds are crossed

8. Viva / Review Questions

Common questions examiners ask for projects in this domain.

1. Which microcontroller / board and sensors are used and why?
2. How does the device send data (Wi-Fi, MQTT, HTTP, Bluetooth)?
3. Where is the sensor data stored and visualised?
4. How is power consumption managed?
5. How would you secure the device and its communication?

9. Source Code & License

This project is developed by killee and published on GitHub under the GNU General Public License v3.0. Please follow the license terms and credit the original author when you use or modify this code.