Kotlin/Native server to manage attendance on a raspberry pi 4B from a python server managing biometric sensors and camera.

Also made a Youtube Video talking about this project

• Raspberry pi (Used in this project is 4B 8gb variant)
• R307 fingerprint scanner with UART to USB Converter
• ssd1305 OLED Display
• Raspberry pi camera
• 4x4 matrix membrane keypad
• Jumper cables and power adapter

Required OS for Raspberry pi: Debian GNU/Linux 12 (bookworm) aarch64

• Clone the repo at the home directory

git clone https://github.com/shub39/RpiAttendance

• Install uv package manager
• Setup the server environment

# Setup
cd RpiAttandance/sensor_server/
uv venv
uv pip install

sudo apt update
sudo apt upgrade
sudo apt install pip python3-opencv python3-numpy cmake
sudo apt install libkms++-dev libfmt-dev libdrm-dev # might require more...

uv pip install rpi-libcamera -C setup-args="-Dversion=unknown"
uv pip install -r requirements.txt

• Setup the cronjob to run server on reboot, file cronjob.sh

• Download the binary from releases to the home directory
• Setup cronjob
• Install android app on a device in the same network as the Raspberry Pi

To build the project from source, you can use the following Gradle commands:

• Build the native server: ./gradlew :server:linkReleaseExecutableLinuxArm64
• Build the Android app: ./gradlew :androidApp:assembleRelease
• Run the Desktop app: ./gradlew :desktopApp:run

• sensor_server : throughly tested python server to manage the sensors using fastapi
• core : shared kotlin models and interfaces throughout the project
• server : Kotlin/Native server, the main server to connect with the client app. Manages connection to the sensor_server and database. Processes business logic
• client : UI and logic for the client app
• androidApp : Build module for the Android App
• desktopApp : Build Module for the Desktop App, Also for hot reload

graph TD
    subgraph "Client Apps"
        androidApp[Android App]
        desktopApp[Desktop App]
    end
    subgraph "Shared Code"
        client[client module]
        core[core module]
    end
    subgraph "Server Side"
        server[server module]
        sensor_server[sensor_server]
        db[(Database)]
    end
    androidApp --> client
    desktopApp --> client
    client --> core
    client -- Ktor RPC --> server
    server --> core
    server -- FastAPI HTTP --> sensor_server
    server --> db

• Framework: Kotlin Multiplatform
• UI: Jetpack Compose for Multiplatform for building the UI for Android, and Desktop.
• Server: Ktor for the server-side application, with Kotlinx RPC for type-safe remote procedure calls between the client and server.
• Database: Room for the local database on the server.
• Dependency Injection: Koin for dependency injection.
• Asynchronous Programming: Kotlin Coroutines for managing background threads and asynchronous operations.
• Serialization: Kotlinx Serialization for serializing and deserializing data between the client and server.

This project is licensed under the GPL-3.0 License. See the LICENSE file for details.