MobileIoT

This repository contains small .NET and Python demos for Raspberry Pi.

The src/MobileIoT folder holds the .NET MAUI application, while src/pi includes Python utilities that run directly on the Pi hardware.

BLE GATT Demo

The Python script at src/pi/bluetoothle_demo.py implements a Bluetooth Low Energy GATT server exposing temperature, humidity and LED control. It matches the UUIDs that the MobileIoT app expects:

• Service UUID: 12345678-1234-1234-1234-1234567890AB
• Temperature Characteristic: UUID 00002A6E-0000-1000-8000-00805F9B34FB
• Humidity Characteristic: UUID 00002A6F-0000-1000-8000-00805F9B34FB
• LED Characteristic: UUID 12345679-1234-1234-1234-1234567890AB

Run the demo with:

python3 bluetoothle_demo.py --azure-iot-hub-connection-string "<connection>"

Telemetry forwarding to Azure IoT Hub or Azure IoT Operations Edge is optional; provide the relevant --azure-* arguments to enable it. See src/pi/README.md for a table of command-line options.

BLE Beacon Demo

A Raspberry Pi can also act as a simple iBeacon for the .NET MAUI app. The Python script at src/pi/beacon_demo.py uses BlueZero to broadcast an iBeacon advertisement with the same UUID used elsewhere in the project. The script accepts parameters for the UUID, major/minor identifiers, adapter selection, and optional runtime duration so you can tailor presence-detection experiments:

sudo python3 beacon_demo.py --uuid 12345678-1234-1234-1234-1234567890AB --major 100 --minor 1 --duration 60

See src/pi/BEACON_SETUP.md for setup instructions and additional context.

USB Serial & Device Demos

The Pi can also communicate with the MAUI app over USB. To enable this, configure the Pi for USB gadget mode (see src/pi/README.md for the exact steps). Two demos are provided:

1. USB Serial (CDC ACM) - load the g_serial driver and run src/pi/serial_demo.py. The MAUI app alternates between the commands "LED_ON" and "LED_OFF" which toggle an LED on GPIO17 and reply with an acknowledgment. Use run_serial_demo.sh to automatically load the gadget driver and forward any command-line arguments to the Python script.
2. USB Bulk Ping - load the g_zero gadget. It echoes any bulk data from the host so the MAUI app's ping function receives the bytes back immediately. The helper run_usb_bulk_echo.sh swaps out g_serial if necessary and activates g_zero in one step.

Thread Protocol Demo

The Thread demo shows how the MAUI app can interact with a Thread mesh network through a Raspberry Pi running OpenThread Border Router (OTBR).

Hybrid mock/live mode - the app starts in mock mode with deterministic synthetic data so it can be used immediately on any platform. Toggle the "Use Live Bridge" switch and enter the Pi's bridge URL to query real Thread status via ot-ctl and perform CoAP echo pings to mesh nodes.

App side

The core logic lives in QiMata.MobileIoT.ThreadDemoCore, a plain net8.0 class library with no MAUI dependencies. The MAUI app references it and provides ThreadPage.xaml with controls for status refresh, CoAP ping, and a scrollable log capped at 200 entries.

Pi side

src/pi/thread_demo.py runs an HTTP bridge on port 8080 and a CoAP echo server on port 5683. Endpoints:

Method	Path	Description
GET	/healthz	Health check
GET	/thread/status	Thread network status
POST	/thread/ping	CoAP echo ping to a mesh node

Prerequisites: OTBR installed and a Thread network commissioned. See src/pi/README.md for setup and run commands.

Running tests

# .NET (from src/MobileIoT/)
dotnet test QiMata.MobileIoT.ThreadDemoCore.Tests

# Python (from repo root)
python -m pytest src/pi/tests -q

Audio Jack Telemetry

An additional demo shows how to transmit sensor data through the Pi's audio jack. See docs/audio_jack_demo.md and the script src/pi/audio_demo.py for details on connecting a TRRS cable and using the minimodem tool to send readings as audio tones. The MobileIoT app has an "Audio Jack" page that listens on the microphone and displays the decoded messages. Run the demo with, for example:

python3 audio_demo.py --sensor dht22 --dht22-pin 4 --interval 3

The script can stream CPU temperature, DHT22 readings, or values from a JSON file by supplying the appropriate --sensor option. Each reading is formatted as comma-separated key/value pairs before being handed to minimodem for FSK modulation. Ensure minimodem is installed (sudo apt-get install minimodem) and the Pi audio output volume is set low enough not to clip the phone input.