The figure 2.1 represents the schematics of the proposed system. The system can be divided into two sections.
1. Data Logging and Monitoring Section
2. Networking Section
2.2.1 DATA LOGGING AND MONITORING SECTION
Data Logging and Monitoring Section consists of Arduino Uno and Sensors MQ-7 for measuring CO, MQ-135 for measuring CO2, MQ -2 for measuring Smoke and LPG and Ultra sonic sensor for measuring distance. The design uses Arduino Uno for data logging from sensors. The reason for choosing Arduino Uno is Arduino Uno having capability to deal with Analog and Digital interfaces as well. The Arduino also having capability to transmit data serially via USB Serial Cable with baud rate 9200 bits/sec. The design uses Analog Voltage from the sensors and communicates to Raspberry Pi using USB serial interface. The Arduino Uno acts as a sensors node. Arduino Uno sends the data logged from sensors CO (MQ-7), CO2 (MQ-135) and LPG/Smoke (MQ -2) to Raspberry Pi B using serial interface cable.
2.2.2 NETWORKING SECTION
Networking section consists of Raspberry Pi, USB Wi-Fi Adaptor, Web cam and Andriod Mobile. The design uses Raspberry Pi B+, it is a mini computer. The Raspberry Pi booted with Raspbian Jessie Lite Operating System. Raspberry Pi having 512 MB RAM, 4 USB Ports, 40 GPIO pins, Video out pin, 3.5mm Audio jack, SoC Broadcom 2835 and supports Wi-Fi through USB Wi-Fi adaptor, LAN through Ethernet Socket 10.
A. Wi-Fi Network
The design uses Mobile Wi-Fi hotspot to set a portable Wi-Fi Network 802.11u IEEE standard. The Wi-Fi hotspot is secured with Wi-Fi Protected Access –Pre Shared Key (WPA-PSK) client authentication method. The Wi-Fi network Service Set Identified (SSID), Network Security Key is configured with Raspberry Pi B+ module.
The design uses Secure Socket Shell (SSH) to connect remote computer through a secured access in an insecure network. SSH provides strong authentication and encrypted data communication between devices on the network. SSH is cryptographic network protocol which uses client-server model. The Design uses Raspberry Pi B+ as a SSH-Server. The SSH-Client application is installed in the mobile, which allows user to login to terminal of the Raspberry Pi B+. From the terminal user will able to execute the commands and programs.
C. Live Stream Network
The video is recorded using Webcam, the webcam communicates to Raspberry Pi B+ using USB Cable 11. The resolution of the webcam can be fixed up to 6048*4032 and maximum frame rate 30fps. The video is recorded using webcam. The webcam communicates Raspberry Pi B+ using USB Communication protocol. The video is live video is streamed on the network by using Real time Streaming Protocol (RTSP), Real time Transport Control Protocol (RTCP).
Open source software package called ‘Motion’ is installed in Raspberry Pi B+. The motion software is configured to broadcast the live stream through the Raspberry Pi B+ (local host) IP Address on the network and it is configured for video for video codec, frame rate, port and resolution etc.
The design uses video codec-mpeg4, port-8081, framesrate-100fps, resolution 640*480. The live stream can be stopped or started from the terminal using SSH-Client on the network. The live video stream can be viewed by any device on the network by accessing IP address of Raspberry Pi B+.
D. Sensor Data Logging and Monitoring
The data from sensors are logged to Arduino Uno. The sensor data is communicated serially to Raspberry Pi B+ using USB serial cable. The Raspberry Pi B+ is configured to run a python program, which get the serial data and displays it on terminal and it writes the same to a specified text file. The text file can be viewed through terminal. Users who are on the same network can login through SSH can view the data by accessing the text file or terminal.