ESP32-S3 Knob Thermostat

A smart thermostat controller built for the Waveshare ESP32-S3-Knob-Touch-LCD-1.8 that controls a Plugwise thermostat via the Homey Pro local REST API.

Features

• Analog Clock - Default view showing current time (Amsterdam timezone with automatic DST)
• Thermostat Control - Adjust target temperature using the rotary encoder
• Touch Navigation - Tap screen to switch between clock and thermostat views
• Visual Feedback - Orange background when heating is active, black when idle
• Debounced Updates - 2-second delay before pushing temperature changes to prevent API spam

Preview

Photos

Hardware

The Waveshare ESP32-S3-Knob-Touch-LCD-1.8:

• Display: 1.8" 360x360 round LCD (ST77916 QSPI)
• Input: Rotary encoder knob + CST816 capacitive touch
• Connectivity: WiFi 802.11 b/g/n
• MCU: ESP32-S3

Architecture

┌─────────────────┐      WiFi/REST       ┌────────────┐      ┌──────────┐
│ ESP32-S3 Knob   │ ──────────────────── │ Homey Pro  │ ──── │ Plugwise │
│ (LVGL UI)       │   Bearer Token Auth  │ (Local IP) │      │ Thermo.  │
└─────────────────┘                      └────────────┘      └──────────┘

Tech Stack

• Framework: PlatformIO + Arduino
• GUI: LVGL v8.4.0
• Display Driver: Arduino_GFX (ST77916)
• HTTP Client: ESP32 HTTPClient
• JSON: ArduinoJson

Setup

1. Copy include/secrets.h.example to include/secrets.h
2. Fill in your credentials:

   #define WIFI_SSID "your-wifi-ssid"
   #define WIFI_PASSWORD "your-wifi-password"
   #define HOMEY_IP "192.168.x.x"
   #define HOMEY_API_KEY "your-homey-api-key"
   #define THERMOSTAT_DEVICE_ID "your-device-uuid"

3. Build and upload with PlatformIO:

   pio run --target upload

Getting Homey API Credentials

1. Go to Homey App → Settings → API Keys → Create
2. Find your thermostat device ID via Homey Developer Tools or API
3. Note your Homey Pro's local IP address

Usage

• Rotate knob - Adjust target temperature (0.5°C steps)
• Tap screen - Toggle between clock and thermostat views
• Wait 2 seconds - Temperature automatically pushed to Homey after adjustment

Project Structure

thermostaat/
├── src/
│   ├── main.cpp              # Application entry point
│   ├── config.h              # Hardware pin definitions
│   ├── hardware/
│   │   ├── display.cpp/h     # ST77916 QSPI display driver
│   │   ├── encoder.cpp/h     # Rotary encoder handling
│   │   └── touch.cpp/h       # CST816 touch driver
│   ├── homey/
│   │   └── homey_api.cpp/h   # Homey REST API client
│   └── ui/
│       ├── ui.cpp/h          # Thermostat UI components
│       └── views.cpp/h       # View manager + clock view
├── include/
│   ├── lv_conf.h             # LVGL configuration
│   ├── secrets.h             # Credentials (gitignored)
│   └── secrets.h.example     # Credentials template
└── platformio.ini            # Build configuration

License

MIT