A Novel Solution for Remote Monitoring of Electrical and Electronic Gadgets Pradipta Biswas University of Kalyani, India 1 Introduction Remote control of electrical and electronic gadgets in domestic and industrial sectors is a widely known phenomenon. The technology for remote control has been changed remarkably with the evolution of Internet and wireless technologies. Recently, smarter bluetooth enabled remote controllers are replacing the infrared-based remote controls. Further, with the spectacular growth in Internet and WWW the remote automation with the aid of Internet and WWW becomes a promising alternative. The recent works on remote control and automation mainly concentrate on the concept of intelligent house [1]. Evolution of bluetooth-enabled devices is one of the major breakthroughs in this ground. Bluetooth based remote controllers are already been developed [1] [2]. The problem with this technology is that the distance between the controller and controlled devices becomes limited to at most 100m [1]. To overcome the distance barrier, the bluetooth controller is kept connected with the Internet [2]. Other than the bluetooth, some distributed systems are also used for remote controlling. Sun Microsystem s JINI based home automation project [3] is an attempt in this respect. In [4], the use of JINI for home automation has been described. The Simple Network Management Protocol (SNMP) is being used for home automation in [5]. In [6], a special PC-type device, namely Information Furnace is used for home automation in a versatile fashion. The PC-type device is integrated to an answering machine, burglar alarm, fax server, Internet router etc. The problem with the existing solutions is that either they need a special type of software [3] [4] or hardware [6] and persistent Internet connectivity [2]. These requirements made the solutions costlier even if deployed in a large scale also. Another problem is that remote control application is confined to home or industrial automation sectors. The present work proposes a software package for remote controlling of electronics or electrical gadgets at a moderate cost. If applied in large concerns, devices can be controlled from a central location or from distant places without having to operate every appliance manually. Time will be saved for controlling and constant monitoring is possible even without the presence of any individual at the site. The system does not require constant Internet connectivity and it needs only a minimum hardware and software. It has enough scope in various fields and can influence the lives of the common man to a large extent. The main advantage of the proposed system is that the installation and running cost of the proposed system will be less than the existing applications of the similar nature.
2 Preliminaries In this section, some basic technologies used in the present work are discussed. 2.1 Email System Electronic mail or email has been around over for two decades. It is a persistence asynchronous message transfer system. An email system has two parts. 1. USER AGENT, which allow people to read and send email. 2. MESSAGE TRANSFER AGENT, which moves the messages from source to destination. Figure 1 shows the architecture of an email system. SMTP Internet Message transfer POP3 server POP3 User agent agent Sending host Mailbox ISP s machine Dial-up connection User s PC Fig1. Architecture of an email system As long as all users work on machines that were directly connected to each other, delivery of emails was accomplished by having the sender establishes a TCP connection to the receiver and then shipping the email over it. However, when people started accessing the Internet by calling their ISP over a modem, it broke down. The SMTP protocol can only be run when a computer is on-line for receiving emails. One solution is to have a message transfer agent on an ISP machine accept email for its customers and store it in their mailboxes on an ISP machine. A new protocol has been created to allow user transfer agents (on client PCs) to contact the message transfer agent (on the ISP s machine) and allow email to be copied from the ISP to the user. This new protocol is Post Office Protocol version 3 (POP3). 2.2 DTMF Technology DTMF is the short form of Dual Tone Multiple Frequency. DTMF is an example of a multi-frequency shift keying (MFSK) system. The system used by touch-tone telephones. Touch tone is a method used by the telephone system to communicate the keys pressed when dialing. Pressing a key on the phone's keypad generates two simultaneous tones, one for the row and one for the column. These are decoded by the exchange to determine which key was pressed. This frequency assignment is implemented using DTMF, which assigns a specific frequency (made up of two separate tones), to each key so that it can
easily be identified by a microprocessor. As a result a voice can't imitate the tones; one tone is generated from a high-frequency group of tones and the other from a low frequency group. A number of companies make microchips that send and receive DTMF signals. The Telephony Application Program Interface (TAPI) provides a way for a program to detect DTMF digits. Today DTMF is used for most call setup to the telephone exchange, at least in the Western world, and trunk signaling is now done out of band using the SS7 signaling system. 2.3 Computer Ports Computer ports are nothing but locations in the memory map which are used for connecting devices such as a trackball, expanded keyboard, flatbed scanner, touch screen, and other device peripherals. The present work used the parallel port for interfacing gadgets. 2.3.1 Parallel port (Printer port) A PC printer port is an inexpensive and yet powerful platform for implementing projects dealing with the control of real world peripherals. The printer port provides eight TTL outputs, five inputs and four bidirectional leads and it provides a very simple means to use the PC interrupt structure. Each parallel port consists of three port addresses; data, status and control port. These addresses are in sequential order. That is, if the data port is at address 0x0378, the corresponding status port is at 0x0379 and the control port is at 0x037a. Fig.2 and Fig. 3 display the pin assignment and port assignment of a parallel port. Fig.2 Pin assignment of a parallel port
Fig.3 Port assignment of a parallel port 3 Proposed System In this section, a brief overview of the workings system is presented. Gadgets that are to be controlled are to be connected to a central PC. This PC can be used for any purpose besides this application. The proposed system will run as a daemon. To interface gadgets the PC needs only a dedicated parallel port. This controller PC has to be attached to POTS or (and) Internet for getting user command from a remote place. The design of the whole system is shown in the Fig. 4. The overall functioning of the system is explained in the next subsection. 3.1 Operation Fig. 4: Overview of the proposed system The system operates in a command response basis. Commands can be given either through email or by dialing a number in a telephone. The operation of the system can be divided into the following four phases. Receiving Command
Interpreting Command Executing Command Sending Acknowledgement Now each of these phases will be discussed in brief. 3.1.1 Receiving Command User instruction can be received either through email or by recognizing a number. In case of email, the system will assume a dedicated mail server operating for the system. At a regular period, it will retrieve the last email as the latest user instruction. For a POP3 server, the steps for retrieving the last email are as follows. Log In to POP3 server by specifying username and password Get present status of the mailbox by STAT command Retrieve the last mail number from the response of the STAT command Retrieve the last mail by RETR command Quit from Mailbox Besides email, command can also be given by DTMF technology. In this case, the number of the phone attached to the modem has to be dialed first. After getting the ringing sound, instruction can be given by dialing a code number. With email the instruction can be given in natural language like Tube ON, Computer Off etc. Currently the system also accepts emails in Bengali other than English. But the problem is the controller PC has to be constantly connected to the Internet. In case of DTMF technology, constant Internet connection is not required, but instruction has to be encoded into specific numbers. 3.1.2 Interpreting Command If the command is given through email, the mail body has to be parsed to get the user instructions (like Tube On, Fan OFF etc.).for emails written in Bengali (or languages other than English), the mail body has to be translated into English before parsing. The details of the language conversion process are not discussed in the present paper. In case of DTMF, interpreting command reduces to recognize the keys pressed. 3.1.3 Executing Command Command execution depends on the actual command given. For controlling interfaced gadgets, a particular bit pattern is sent to parallel port. If the command is to send a report, then it can be constructed on the fly from the logs at the controller PC. 3.1.4 Sending Acknowledgement After executing the command an acknowledgement will be sent to the user. In case of emails, the response is an elaborate description of the present status of the last executed command sent as an email. The mail body has to be converted into the language in which the commanding email was received. In case of DTMF technology, the response only states whether the last given command is executed successfully or not.
4 Implementation Strategy From the implementation point of view the proposed system has two distinct parts Software part Hardware part The software part concentrates on designing the software for interaction with end users. The hardware part deals with designing an interfacing circuit for electrical and electronic gadgets. For the current implementation, the software is designed using JAVA and Visual Basic. The email receiving and sending program is written using Java network sockets. The username, password, incoming and outgoing mail server name are taken from user during initial set up of the system. The JAVA program opens a socket with the incoming mail server to get user command. Then it sends the POP3 commands to retrieve the last email (Sec. 3.1.1.). The program searches for known patterns within the mail body. The Pattern and Matcher classes are used for pattern matching purpose. After interpreting the command it sends a bit pattern to the parallel port to control attached gadgets. The parallel port accessing software has used another DLL file viz. Inpout32.dll, which is downloadable from the site www.logix4u.net at free of cost. For acknowledgement sending the program first creates the status report. Then it opens a socket connection with outgoing mail server and sends the status report in the mail body. The DTMF portion of the software is developed in Visual Basic with a downloaded ActiveX viz. VTAPI.ocx. This ActiveX is downloadable from the site of SoftCab Corporation (www.softcab.com) at free of cost. The hardware interfacing part is developed using transistor switches and 6V relay circuits. The interfacing circuit is shown in fig. 5. Fig. 5 Interfacing circuit
The parallel port can provide TTL output (Sec 2.3.1). It was noted that it provided 3.3 V when a logical 1 is send to it. The transistor switch is turned on only at 1.5 V. The circuit shows a connection with the data port (pin no. 2) of a parallel port. So when a logical 1 is sent to the pin no. 2 of the data port, the relay circuit is turned on. The 220 volt gadgets are connected to the relay circuit and they are switched on and off according to the relay. Thus by sending a bit pattern at the parallel port, the 220V electrical and electronic gadgets can be controlled. The circuit is tested with a 25W light bulb, 60W Tubes and 60W Fans. In each case the system has operated correctly. 5 Application The novelty of the system compared to the existing similar applications is illustrated in the following points. The system is very cheap. It does not need a dedicated computer or computer like embedded system and any specialized software framework. The cost of the interfacing circuit is only Rs. 50 per gadget or in that order. The system can be operated without constant Internet connection. For simple on/off purpose, any sort of electrical and electronic gadget can be interfaced with the PC. However for complex controlling, the gadgets should be equipped with special control circuit so that the gadgets can be controlled by applying control voltage from outside. The system will not interfere with any existing application. The controller PC can be used for any other purpose beside this system. The software portion of the system will run as a daemon in the controller PC. The interface of the system is very user friendly. It can accept command in more than one language. Since commands can be given through email or telephone, so the system can be operated even from a roadside STD booth or from an internet connected PDA also. Due to little installation and running cost and associated overheads the system can be deployed in a number of applications in various domains. Some of them are mentioned below. Automating Rural Kiosks Rural kiosks are the means of spreading the scope of information technology at villages. Controlling and monitoring the rural kiosks locally may become a problem for lack of local experts. It is also costly for training and appointing local administrator at each kiosk. The proposed system offers a very good solution of these problems. The system can be used to control and monitor the rural kiosks from a central location. For example, using the proposed system the computer and accessories of a kiosk can be powered on and off from a remote location. If an air conditioner is used at a kiosk in a hot place the AC temperature can be controlled and monitored remotely. The computer sessions can be monitored also by requesting the event logs by the central controller.
Home Automation The proposed system is a novel solution to develop an intelligent or smart house at a nominal cost. All electrical and electronic home gadgets including light, fans, refrigerator, and air conditioner etc. can be operated from a remote place. Instead of home the same system can be deployed at an office to develop an intelligent office assistant. Industrial Automation This system can be used in industries for remote process monitoring and controlling. The operating instructions of a machine can be given through email. The status of an operation can be continuously monitored by the acknowledgement emails. These emails can be sent and received by a desktop PC. So sitting at an office desk an operator can control and monitor a complex operation by merely sending and receiving some emails. Assistive Technology The system is a good candidate to be considered for assistive technology to some extent. The system can be used to send several sensor data from an intelligent house to a remote clinic. The clinic can send instructions to the actuators at the house to control the house environment. As for example on getting the blood pressure and body temperature of a patient at an intelligent house through an email, the clinic can regulate the fan speed at a room just by dialing a number. 6 Conclusions The present paper discusses about a system for remote monitoring of electrical and electronic gadgets. The gadgets can be controlled either by sending email or by dialing a phone number. The proposed system is affordable than the existing similar applications in terms of both installation cost and running cost. Most of the existing applications in the sector of remote monitoring, mainly concentrates on home automation or industrial automation. In the present paper, a new area of application, viz. automatic monitoring of rural kiosks is also identified. To make the system user friendly, the interface is designed to support more than one language. A possible implementation scenario of the proposed system is also being discussed. The system is planned to support more input modes in future. Currently, we are working to operate the system by SMS beside email and telephone dialing. We are also in the process of designing a web site through which the user can access and monitor their gadgets from anywhere in the world. Acknowledgement We are thankful to Prof. R. N. Ghosh, St. Thomas College of Engineering and Technology, Kolkata for his valuable suggestions and guidance in this work.
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