DecentBridge

A bridge server that connects your DE1 espresso machine and Bluetooth scale to the network, letting you control them from any app or browser.

What Does It Do?

DecentBridge runs on your DE1 tablet (or any computer) and:

1. Connects to your DE1 via Bluetooth
2. Connects to your scale via Bluetooth (supports 14 different scales)
3. Provides a web API so other apps can control your machine

This means you can:

• Control your DE1 from a custom app
• Monitor shots in real-time from your phone or computer
• Build your own coffee automation tools
• Use any scale with any app (the bridge handles the translation)

Supported Scales

• Acaia (Lunar, Pearl, Pyxis)
• Atomheart Eclair
• Bookoo
• Decent Scale
• DiFluid
• Eureka Precisa
• Felicita (Arc, Parallel)
• Hiroia Jimmy
• Skale
• SmartChef
• SoloBarista
• Varia Aku

Quick Start

Option 1: Install Pre-built APK (Easiest)

1. Download the latest APK from Releases
2. Connect to your DE1 tablet via ADB:

   adb connect 192.168.1.208
   

3. Install the APK:

   adb install DecentBridge.apk
   

4. Open "DecentBridge" from the app drawer
5. The server starts automatically on ports 8080 (HTTP) and 8081 (WebSocket)

Option 2: Build From Source

See Building From Source below.

Using the API

Once DecentBridge is running, you can access your DE1 from any device on the same network.

Check if it's working

Open a browser and go to:

http://192.168.1.208:8080/api/v1/devices

You should see a list of connected devices (DE1 and/or scale).

Example: Get machine state

curl http://192.168.1.208:8080/api/v1/machine/state

Returns:

{
  "state": {"state": "Idle", "substate": "Ready"},
  "pressure": 0.0,
  "flow": 0.0,
  "groupTemperature": 92.5,
  "steamTemperature": 140.0
}

Example: Tare the scale

curl -X PUT http://192.168.1.208:8080/api/v1/scale/tare

Example: Start espresso

curl -X PUT http://192.168.1.208:8080/api/v1/machine/state/espresso

Real-time data via WebSocket

Connect to ws://192.168.1.208:8081/ws/v1/machine/snapshot to receive live shot data:

const ws = new WebSocket('ws://192.168.1.208:8081/ws/v1/machine/snapshot');
ws.onmessage = (event) => {
  const data = JSON.parse(event.data);
  console.log(`Pressure: ${data.pressure} bar, Flow: ${data.flow} ml/s`);
};

Building From Source

Requirements

• Qt 6.10 or later - Download from qt.io
  • Select these components: Core, Bluetooth, Network, WebSockets, Gui
• CMake 3.21 or later - Usually included with Qt
• For Android builds: Android SDK and NDK

Building for Windows

1. Open a terminal (Command Prompt or PowerShell)

2. Navigate to the project:

   cd C:\code\DecentBridge
   

3. Configure the build (adjust the Qt path to match your installation):

   cmake -B build -DCMAKE_PREFIX_PATH="C:/Qt/6.10.1/msvc2022_64"
   

4. Build:

   cmake --build build --config Release
   

5. Run:

   build\Release\DecentBridge.exe
   

Building for Android

1. Make sure you have Android SDK and NDK installed (Qt Maintenance Tool can install these)

2. Configure the build:

   cmake -S . -B build/android \
     -G Ninja \
     -DCMAKE_MAKE_PROGRAM="C:/Qt/Tools/Ninja/ninja.exe" \
     -DCMAKE_BUILD_TYPE=Release \
     -DCMAKE_TOOLCHAIN_FILE="C:/Users/YOUR_USERNAME/AppData/Local/Android/Sdk/ndk/27.2.12479018/build/cmake/android.toolchain.cmake" \
     -DANDROID_ABI=arm64-v8a \
     -DANDROID_PLATFORM=android-28 \
     -DANDROID_SDK_ROOT="C:/Users/YOUR_USERNAME/AppData/Local/Android/Sdk" \
     -DQT_HOST_PATH="C:/Qt/6.10.1/msvc2022_64" \
     -DCMAKE_PREFIX_PATH="C:/Qt/6.10.1/android_arm64_v8a" \
     -DCMAKE_FIND_ROOT_PATH="C:/Qt/6.10.1/android_arm64_v8a"

   Replace YOUR_USERNAME with your Windows username.

3. Build:

   cmake --build build/android
   

4. The APK will be at:

   build/android/android-build/build/outputs/apk/debug/android-build-debug.apk
   

Building with Qt Creator (Easiest)

1. Open Qt Creator
2. File → Open File or Project
3. Select CMakeLists.txt from the DecentBridge folder
4. Select your kit (Desktop for PC, Android for tablet)
5. Click Build (Ctrl+B)
6. Click Run (Ctrl+R) or deploy to device

API Reference

HTTP Endpoints (Port 8080)

Method	Endpoint	Description
GET	/api/v1/devices	List connected devices
GET	/api/v1/devices/scan	Start scanning for devices
GET	/api/v1/machine/info	Get machine info (model, firmware)
GET	/api/v1/machine/state	Get current state and sensor readings
PUT	/api/v1/machine/state/{state}	Change state (idle, espresso, steam, water, flush)
GET	/api/v1/machine/settings	Get machine settings
POST	/api/v1/machine/settings	Update machine settings
POST	/api/v1/machine/profile	Upload a profile
PUT	/api/v1/scale/tare	Tare the scale

WebSocket Channels (Port 8081)

Channel	Description
/ws/v1/machine/snapshot	Real-time pressure, flow, temperature
/ws/v1/scale/snapshot	Real-time weight and flow rate
/ws/v1/machine/waterLevels	Water tank levels
/ws/v1/machine/shotSettings	Shot settings updates

Troubleshooting

"DE1 not connected"

• Make sure Bluetooth is enabled on the device running DecentBridge
• The DE1 must be powered on and not connected to another app
• Check that you're on the same network as the DE1 tablet

"Scale not found"

• Make sure the scale is powered on and in pairing mode
• Some scales need to be woken up first (step on them or press a button)
• Check that no other app is connected to the scale

Can't connect to the API

• Verify the IP address of the device running DecentBridge
• Make sure ports 8080 and 8081 are not blocked by a firewall
• Check that both devices are on the same WiFi network

Android build fails

• Make sure Android SDK and NDK paths are correct
• Try cleaning the build: rm -rf build/android and rebuild
• Check that Qt for Android is installed via Qt Maintenance Tool

License

MIT License - See LICENSE file for details.

Contributing

Contributions are welcome! Please open an issue or pull request on GitHub.

Acknowledgments

• Scale implementations based on Decenza
• API design inspired by ReaPrime