elvinhome CTRL ONE ePaper Room Controller
Product Description
The CTRL ONE is a wall-mounted or desktop ePaper room controller built around the Espressif ESP32-C6 (single-core RISC-V). It is a touch panel, information display and air-quality monitor in one, with a flexible add-on system that turns it into a fully-featured smart thermostat. It ships with ESPHome pre-flashed out of the box.
The onboard Sensirion SCD40 sensor measures temperature, humidity and CO2. The sensor sits in a corner cutout, separated from the heat-generating internals and shielded from draughts and direct sunlight. It samples every 30 seconds by default and is configurable down to every 5 seconds.
The 300 x 400 ePaper touchscreen supports partial refresh, along with a front light (colloquially known as a backlight, but it is technically in front of the display layer). The front-facing ambient light sensor is configured to automatically set the brightness.
The provided configuration creates a grid and widget system in LVGL. Out of the box, it shows its own sensor readings; add widgets on a 4 x 6 grid to pull in Home Assistant entities and control lights, fans, curtains and more with buttons and sliders.
Key hardware:
- Espressif ESP32-C6 (RISC-V) with 2.4 GHz WiFi 6; Zigbee and Thread are possible through configuration changes.
- 4.2-inch ePaper display (Goodisplay GDEY042T81, 300 x 400 portrait) with touchscreen (FT63x6) and auto-dimming front light, driven over SPI.
- Sensirion SCD40 sensor measuring CO2, temperature and humidity over I2C.
- Ambient light sensor (ALS-PT19) on an ADC pin.
- Rear-facing RGB indicator LED.
- USB-C port for power and flashing (exposes the ESP32-C6 USB interface).
- 8-pin add-on connector on the back exposing GPIO, I2C, UART and power (up to 28 V), for the 24 VAC thermostat, buzzer and breakout add-ons.
The device is powered over USB-C or through the add-on slot. It is available with a glossy-white acrylic or natural-oak bezel, and mounts to a standard 60 mm European recessed wall box or sits on the included stand. The enclosure is made of 3D-printed and laser-cut parts, with open-source mount and bezel designs.
The firmware is GPLv3 licensed and hosted on Codeberg, targeting ESPHome 2026.7.0 or higher.
GPIO Pinout
| Pin | Function |
|---|---|
| GPIO1 | Add-on connector general purpose pin |
| GPIO2 | I2C SCL |
| GPIO3 | I2C SDA |
| GPIO4 | Touchscreen interrupt (FT63x6) |
| GPIO5 | Touchscreen reset (FT63x6) |
| GPIO6 | Ambient light ADC |
| GPIO7 | Screen front-light PWM (LEDC) |
| GPIO8 | Indicator LED — red (inverted) |
| GPIO14 | Indicator LED — blue (inverted) |
| GPIO15 | Indicator LED — green (inverted) |
| GPIO16 | Add-on connector — UART TX |
| GPIO17 | Add-on connector — UART RX |
| GPIO18 | SPI MOSI (display) |
| GPIO19 | SPI CLK (display) |
| GPIO20 | Display CS |
| GPIO21 | Display DC |
| GPIO22 | Display reset |
| GPIO23 | Display busy |
Basic Configuration
This configuration is taken from the elvinhome Codeberg repository. For the source code of all sub-packages, check the repository.
The current firmware configuration is fetched live from the upstream repository:
# Loading https://codeberg.org/elvinhome/ctrl-one/src/branch/main/esphome/ctrl-one.yaml…Notes
- The ePaper display uses the standard ESPHome
epaper_spiplatform (Goodisplay GDEY042T81). The touchscreen is the FT63x6 on the shared I2C bus. - The add-on connector’s relay output and buzzer both use GPIO1 (see the
addons/folder in the firmware repository for the full add-on configs). The 24 VAC thermostat add-on turns the device into a standalone thermostat that replaces common wired thermostats, powered by the heating system’s own 24 V AC supply. - The rear-facing notification LED is intended for short pulses only and not to be left permanently on. The heat from the light interferes with the temperature readings, so they are disabled while the light is on.
Links
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