Elderly Activity Monitoring System

This project aims to prevent lonely deaths among elderly individuals living alone by providing a privacy-friendly home monitoring solution. Unlike traditional monitoring systems, this approach does not use cameras or wearable devices, ensuring a non-intrusive and respectful solution for elderly care. The system utilizes various sensors to track motion and activity patterns, transmitting data via a home gateway. If prolonged inactivity is detected, a warning message is sent to caregivers via the user interface.

This project is divided into multiple repositories:
[Click Details] -> End-Node, Home-Gateway, Server

 ┌──────────────┐           ┌──────────────────┐           ┌────────────┐           ┌────────┐
 │   End Node   │     →     │   Home Gateway   │     →     │   Server   │     →     │   UI   │
 └──────────────┘           │         │        │           └────────────┘           └────────┘
                   (ZigBee) │         │        │   (MQTT)                (WebSocket)
                            │    MQTT Broker   │
                            └──────────────────┘  

Overview

The Arduino UNO boards are connected with various sensors to detect pressure, sound, and human movement. Each Arduino UNO is connected to a ZigBee module and shield, allowing the collected sensor data to be transmitted to the home gateway using the ZigBee protocol.

Setup & Install

1. Initialize Arduino Board (Without XBee Shield)

• Connect the board to your computer, install Arduino IDE, and select the correct Board and Port in Tools.
• Upload an empty sketch to reset the board:

  void setup() {}  
  void loop() {}

2. Install XCTU & Configure XBee

• Download XCTU and install it.
• Attach the XBee shield, set it to USB mode, and configure the module in XCTU using ZigBee Settings.

3. Upload Code & Enable XBee Communication

• Keep the XBee shield in USB mode and use Arduino IDE to upload the required code.
• After uploading, switch the XBee shield to XBee mode and start communication.

ZigBee Settings

<Coordinator>
- ID: Set the same ID for all nodes to communicate.
- JV: Disabled
- CE: Enabled
- DH: 0
- DL: FFFF
- API: API enabled with escaping
- BD: 9600

<Router>
- ID: Set the same ID for all nodes to communicate.
- JV: Enabled
- DH, DL: Set to the coordinator's MAC address.
- API: API enabled with escaping

API 2 Mode Data Explanation

ZigBee API 2 Mode Overview

• Ensures reliable transmission by escaping specific control bytes (0x7E, 0x7D, 0x11, 0x13).
• Escaped bytes are prefixed with 0x7D and XOR-ed with 0x20, requiring decoding.
• Decoding rule: Any byte after 0x7D must be XOR-ed with 0x20 to restore its original value.
• Example: 7D 33 → 33 ^ 20 = 13 → Restored to 0x13.

Example of Received API 2 Frame

When using sensor data transmission via XBee in API 2 Mode, a received frame may look like this:

7E 00 0D 90 00 7D 33 A2 00 41 FC B7 A4 12 9A 01 34 41

Breakdown of the Frame

Byte(s)	Description	Value	Explanation
7E	Start Delimiter	0x7E	Indicates the beginning of an API frame.
00 0D	Length	0x000D (13 bytes)	Length of the remaining bytes in the frame.
90	Frame Type	0x90 (RX Indicator)	Received data frame from another XBee device.
00 7D 33 A2 00 41 FC B7 A4	Source Address	0x0013A20041FCB7A4	MAC address of the sender (escaped).
12 9A	16-bit Network Address	0x129A	Network address of the sender.
01	Receive Options	0x01	Acknowledgment received.
34	RF Data	0x34	Actual data payload received.
41	Checksum	0x41	Validates data integrity.

End-Node Settings

- Arduino IDE Version: 2.2.1
- XCTU Version: 6.5.13.2

End-Node Components

- Arduino UNO
- Pressure Sensor(FSR 402 Solder Tabs [30-81794])
- Sound Sens9or(SZH-EK033)
- PIR Sensor(HC-SR501)
- ZigBee Module(XBee ZigBee TH(S2C) - XB24CZ7WIT-004)
- XBee Shield(XBee Shield 3.0)

Circuit Description

The connections between each sensor and the Arduino UNO board are as follows:

1. Pressure Sensor:
   - VCC: Connected to 5V on the Arduino
   - GND: Connected to GND on the Arduino
   - OUT: Connected to an analog pin on the Arduino(A0)

2. Sound Sensor:
   - VCC: Connected to 5V on the Arduino
   - GND: Connected to GND on the Arduino
   - OUT: Connected to an analog pin on the Arduino(A0)

3. PIR Sensor:
   - VCC: Connected to 5V on the Arduino
   - GND: Connected to GND on the Arduino
   - OUT: Connected to a digital pin on the Arduino(pin 13)

4. XBee Shield:
   - Mounted directly on top of the Arduino UNO board
   - The XBee module is inserted into the socket on the Shield