Aether

Aether

Aether is a comprehensive air quality monitor by Syntropy Labs built around an ESP32-C3, a Sensirion SEN66 sensor, and a 3.7" e-paper display. It measures CO2, Temperature, Humidity, PM1.0, PM2.5, PM4.0, PM10, VOC index, and NOx index, and exposes those readings on-device, on the local network, and through Home Assistant.

Repo Guide

Contents

• Features
• Hardware
• Assembly
• Firmware Setup
  • Flashing firmware onto a device
  • Firmware development
• Using Aether
  • Normal operation
  • Wi-Fi setup and behavior
  • Side button behavior
  • Local web UI
  • Home Assistant & ESPHome API
  • Updates
• License

Features

• Measures CO2, Temperature, Humidity, PM1.0, PM2.5, PM4.0, PM10, VOC index, and NOx index using the Sensirion SEN66
• Displays live readings on a 416x240 3.7" e-paper panel
• Serves a local web dashboard from the device itself
• Supports ESPHome / Home Assistant integration
• Supports USB factory flashing, firmware recovery, and OTA updates
• Fully local, and can run with or without Wi-Fi

Hardware

To build one Aether unit, the following core parts are needed:

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Alternative Display Compatibility

The Aether PCB implements the standard 24-pin FPC e-paper interface. While designed for the 3.7" GDEY037T03, it is hardware-compatible with many other common e-paper panels (e.g., those using SSD1680, UC8151D, and IL0373 driver ICs). Please note that these alternative displays have not yet been tested or confirmed to work with this device.

If you choose to use an alternative display, you will need to:

1. Update the firmware to instantiate the correct GxEPD2 display driver class.
2. Modify the enclosure design to physically fit the new panel dimensions.

For specific supported ICs and detailed firmware instructions, see display-compatibility.md.

Assembly

High-level assembly flow:

1. Press-fit the SEN66 into the enclosure body.

2. Connect the e-paper display to the PCB with the FPC connector.

3. Press-fit the PCB into the enclosure body.

4. Connect 6-pin JST GH Cable.

5. Bring display over in position above the PCB.

6. Attach the display cover.

7. Secure the assembly from the bottom with the two M3 fasteners.

Firmware Setup

Any Aether devices purchased through Syntropy Labs are pre-flashed with device firmware and fully tested

Flashing firmware onto a device

For a new board or a device that needs recovery:

1. Connect Aether to your computer over USB.
2. Open the Aether WebUSB flashing tool and go to Firmware & Updates.
3. Click Install Aether firmware under Install or Update over USB.
4. Keep the page open until flashing is complete.
5. Let the device boot.

For a device that is already set up and just needs newer firmware:

• Over Wi-Fi (recommended): open the device's local web UI, go to Firmware & updates, and click Update. Home Assistant offers the same update.
• Over USB: follow the steps above. When the connected device is already running Aether firmware, the flasher offers an update that keeps your Wi-Fi and settings instead of erasing the device.

Note: The flashing page in www/ is built around ESP Web Tools / Web Serial and requires desktop Chrome or Edge.

Firmware development

If you are working on the ESPHome firmware, use the latest ESPHome release. Releases are built with it, and CI checks every PR against it. The default PlatformIO toolchain needs Python 3.12–3.14:

pip install --upgrade esphome
git clone https://github.com/EnriqueNeyra/aether.git
cd aether/firmware

esphome config aether.yaml
esphome compile aether.yaml
esphome run aether.yaml

Release firmware can't be flashed over Wi-Fi. To iterate over Wi-Fi, flash aether-dev.yaml over USB once, then use esphome run aether-dev.yaml --device <device-ip>.

To try ESPHome's native ESP-IDF toolchain (the default once toolchain: platformio is removed in ESPHome 2027.2.0), pass -s toolchain esp-idf, e.g. esphome -s toolchain esp-idf compile aether.yaml.

Using Aether

Normal operation

Once powered, Aether reads the SEN66 and refreshes both the on-device display and the local web dashboard. Temperature can be shown in either Fahrenheit or Celsius.

Wi-Fi setup and behavior

On boot, Aether will expose a temporary setup access point so you can connect it to Wi-Fi through the captive portal flow. The network will appear as aether-XXXXXX.

• If you want local web UI access, network-based ota updates, or Home Assistant integration, connect the device to Wi-Fi during setup.
• If you do not configure Wi-Fi, the device will still work as a standalone monitor fully offline.

Once connected to the access point, you will automatically be redirected to the captive portal. Select your network and enter the password to connect. Once connected to Wi-Fi, the device also hosts its local web UI at aether-XXXXXX.local or the device's local IP.

Side button behavior

The side / boot button supports multiple actions:

• Short press (tap, under 1 second): toggles between the normal dashboard and the info screen
• Long press (hold ~3 seconds) from the normal screen: enters factory reset confirmation
• Long press (hold ~3 seconds) again on the reset screen: confirms the factory reset flow
• Long press (hold ~3 seconds) on the info screen while Wi-Fi is not connected: reboots the device, which brings the setup access point back after offline mode

Local web UI

When Aether is on your network, it serves a local browser-based dashboard directly from the device. That UI includes:

• A live environment view for sensor readings
• Temperature unit switching
• Firmware version and update status
• A way to trigger firmware updates from the device UI

Home Assistant & ESPHome API

Because Aether runs ESPHome, it features a native API over Wi-Fi. This allows for:

• Automatic Home Assistant Integration: Aether will automatically appear in Home Assistant integrations dashboard once connected to your network. It exposes all 9 sensor metrics (CO2, temperature, humidity, PM1.0, PM2.5, PM4.0, PM10, VOC index, and NOx index).

• Custom Integrations: You can integrate Aether into your own software or scripts using its local HTTP API. Exposed endpoints include:
  • GET /api/state - Returns a JSON object with all current sensor metrics and device status.
  • POST /api/temp_unit?unit=C|F - Changes the preferred temperature unit.
  • POST /api/check_update - Asks the device to re-check for a firmware update now.
  • POST /api/perform_update - Triggers the device to immediately begin downloading and installing the latest firmware update over HTTPS (if one is available).

Updates

Aether supports more than one update path:

• Local USB flashing through the WebUSB flashing tool (source located in www/)
• In-device update flow through the local web UI
• Home Assistant when the device is online

Use the USB flashing page for first-time setup and recovery. Use the local web UI for routine updates on devices that are already deployed.

License

Aether is licensed per directory:

• Firmware (firmware/): GNU General Public License v3. The firmware is built on GPLv3 code (ESPHome's C++ runtime and the GxEPD2 display driver), so it and the firmware binaries built from it are distributed under GPLv3.
• Everything else (hardware, PCB and manufacturing files, enclosure, website, and documentation): Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. See LICENSE.

Third-party components keep their own licenses, including the fonts in firmware/components/aether_epaper/fonts/ and the libraries the firmware is built with.