Security and Authentication Issues of an Embedded System Designed and Implemented for Interactive Internet Users

Security and Authentication Issues of an Embedded System Designed and Implemented for Interactive Internet Users

Siddhartha Baruah (Gauhati University, India), Anjana Kakoty Mahanta (Gauhati University, India) and Kanak Ch Sarma (Gauhati University, India)
DOI: 10.4018/978-1-4666-0978-5.ch011
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Abstract

Though embedded applications were originally built on standalone devices, nowadays these devices require a growing integration with other systems through their interconnection with TCP/IP networks. Web Services, which provide a service oriented distributed architecture for the interconnection of systems through TCP/IP networks, have been widely adopted for the integration of business applications, but this sort of integration is still not widely provided by embedded applications. The present work aims to demonstrate the feasibility of using Web Services for the integration of embedded applications running on heterogeneous architectures. This is achieved through the provision of a support for the development and deployment of web services for embedded applications. Basic objective of the system developed is to monitor and control Humidity and Temperature through Internet using interactive computer front end. The feasibility of this approach in terms of security and authentications of its Internet users is demonstrated by developing an mail server along with application deployed. Mail server keeps track of authorised users’ with login password and email ID in a database table. This information is used to identify authorised users who are allowed to make changes in control parameters of the stated embedded application.
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Introduction

System developed for the stated study is a microcontroller based embedded system for monitoring and controlling of parameters temperature and humidity. Microcontroller based embedded systems designed for monitoring and controlling of parameters like temperature and humidity is very essential in some industrial as well as research setups (National Instruments, n.d.; Mazidi & Mazidi, 2007). Developed system can be implemented using simple client server technology as well as web technology (Baruah, Kakoti Mahanta, & Sharma, 2009; 2010). Embedded hardware circuit is fabricated in to two separate digital circuits connecting to two com ports of Embedded server. First circuit will monitor temperature and humidity and display same in LCD. Application program executed in computer reads COM port and display the same in monitor and store in database. This program also continuously monitor the sense values against some user entered control values of humidity and temperature at which controlling action has to be carried out. User entered control values are stored in a separate database table so that time to time different values can be set as per requirement. Display of stored value and generation of graph can be also obtained as per choice of user. Second digital circuit will provide necessary hardware control of devices for controlling of temperature and humidity automatically when sense value reaches control value of temperature and humidity stored in database. As a web enable system monitoring and controlling of the system made feasible through web clients anywhere from web with necessary interactive front end and browser configuration. Figure 1 depicts Hardware configuration of boards with Embedded Server.

Figure 1.

Hardware configuration of boards with embedded server

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Schematic Description Of The Functioning Components

Figure 2 below shows schematic diagrams of a Monitoring circuit board and Controlling circuit board, respectively.

Figure 2.

Schematic diagrams

Power Supply Section

The regulated power supply section made with full wave rectifier (with IN 4007 diodes) using voltage regulator IC 7805 and IC 7812 which provide a constant voltage of 5V to the circuit as well as constant 12V to relays.

Analog to Digital Conversion Section

Analog parameters temperature and humidity are converted into digital by ADC 0809 which is an 8 channels microprocessor compatible ADC with easy availability (National Semiconductor Corporation, 2002). It will convert the analog signal of the transducer to digital value with respect to the reference voltage which is 2.5V in proposed system. This reference voltage is obtained using TL431, which is a programmable shunt voltage reference with output voltage range of 2.5V to 36V and works like zener diode (ST Microelectronics, 2002). For the conversion ADC requires a reference frequency which is supplied from 555 IC in the form of astable oscillator. The conversion frequency is kept around 150 kHz.

Sensor Used

Sensor used for temperature measurement is LM 35.LM 35 is calibrated in ºC and is linear in +10 mV/ ºC scale factor with 0.5ºC accuracy (National Semiconductor Corporation, 2000) and no external calibration is needed. It uses humidity sensor LM324DG (Atmel Corporation, 2000) Amplifier circuit is used to amplify the electrical characteristic obtained through the transducer to raise the strength sufficiently.

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