13-08-2012, 09:55 AM
Project on Remote Management System
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Abstract
In an office/home environment, users need to switch on & off different electronic components. So at that time users have to go to the location to manipulate the devices. But it is not possible when the user is far away from those devices. This is the requirement for building remote management system.
The Remote Management System which uses to manage electronic components in an office or home by using a remote control method. For that task PSTN (wired) phone line or through GSM network have to use as the communication method. In any office or home need an assigned person to manipulate those appliances. Remote management systems will supply dedicated number and instructions to manipulate those components.
Therefore we had to research about some technologies which are available with home appliances systems. So it needs to consider about technologies use in home appliances system, DTMF signaling is cost effective, easy to manage and available technology to enhance with remote management. Not only DTMF, it needs some mechanism to derive values out from different frequency ranges. After passing a signal, the system needs a component to process the functionalities of system. Therefore the system has used a microcontroller which is cost effective and also intergraded with system requirements. Then onwards, it only needs relays, resistors, capacitors which operate with other electronic equipments.
The Remote Management System is very capable with handling interrupts and also implemented some methods to backup if any function filed .After all of this implementation Remote Management System is very cost effective, user friendly appliances which can plant in home or office needs.
Introduction
People’s requirements are changing with their lifestyles. And also the modern society consists of easy living styles. And this is very highly mobile society according their needs too. In this case they have requirement of accessing their assets while they are in a move. So, the applications come in future for user requirements must available with distant access. This is more effective than physical accesses when considering recent home/office requirements.
Therefore Remote controlling systems for object management are popular topic in telecommunication and electronic fields. This project, which comes to answer above requirements, is using GSM technology and some other components. And whole application is hardware driven to functions with above technologies. Circuit design for this project is having functions to split frequencies and decode signals to output channels too.
The task of this system was building a remote management system to manage home/office appliances .Here ,In this system, was going to switch on some electronic components according to different signal codes and those codes were sending through a GSM call as a DTMF signal. At the receiver end phone call has connected with mechanism which can split multiple frequencies at the moment. Due to those divided binary values, relays were activated to enable or disable relevant equipments.
Background
Normally people use switches as a controlling method. Infrared remote control switch, wireless remote control switches, light activated switches are becoming popular as controlling methods since last few years. But these technologies have their own limitations. Laser beams are harmful to mankind. Some technologies like IR remote control are used for short distance applications. Due to those reasons researchers were looking for stable, available method of controlling for home/office appliances systems. And this research was to identify technical efforts of those projects and it helped to output a best solution.
Control of Remote Domestic System Using DTMF
The domestic control system has controlled by using mobile phone, that mobile phone should have registered in a communication service and a computer, which can receive a call from another phone. In here, a method has proposed to use the DTMF (Dual Tone Multi Frequency) generated when a keypad button of the mobile phone has pressed by the user. The mobile phone user controls the system by sending the DTMF tone to the access point. By using this fundamental principle, it can be extensive to numerous applications. Such as switch on or switch off home appliances, warning systems, flash lights, cameras, motors, irrigation systems and so on. Those prearranged action are stored in microcontroller and can manipulate with other systems serially.
Project Report
In this feature, it discusses Remote Management System project, which tries to put forward solutions to the challenges raised at developing of Remote Management. A few other researches in this field also have tried to come back with special methods. Even though they are not user-friendly or little bit expensive than the Remote Management System. Several functions which have identified in background also developed in the Remote Management System too. In development phase, the system development had to consider about simplicity, user friendly, cost, backup methods and few other challenges.
In the Remote management System section, it has mentioned about functions of project developments. And in further discussion technologies and its function are also discussed. DTMF signaling, PIC micro controller, frequency splitter, and relays were some technologies used in system development. Circuit designing, program Micro controller are some topics Highlighted in project implementation. In this thesis, it has mentioned about some errors met at the testing period. Drawbacks of developed system and future developments has discussed to enhance quality of the system are mentioned in conclusion.
Remote Management System
Due to rise of daily needs, there are some considerable changes are happening in daily life style of modern people. Because of that, they are in a hurry of daily activities. So a single second has an elevated value in their lives .Therefore people need a control system for their assets while they are far away or travelling away. So there are many home appliances systems have introduced to the world with various technologies.
Remote management system is a proper answer for above challenges. It has been introduced with user-friendly, simple methodology to control electronic devices remotely. A mobile phone is a device available with everybody in these days. And establishment of a call via GSM or wired line will cost a very less expense. Also a cheap phone has the ability to work with DTMF signals.
The user has to established a call between a dedicated number provided by remote management system via wired or GSM network. And the system has integrated auto answering mode to connect with the user. So according to user requirement they can press the required number of the required device while he is on the call. So pressing that number after “#” (#1) means to switch on status of the device and pressing same number after “0” (01) means switch off status of the device. That is the simple mechanism of Remote Management System to control the dedicated devices. The Specialty is the user can call through a wired or a wireless phone.
DTMF signaling
As discussed as earlier DTMF signaling has used for control an application from a remote location. So DTMF signaling is sending telecommunication signal between two telephone devices via voice frequency used in GSM network or PSTN network. So a touch tone comes with push button action, has used as the signal. It starts functioning by rapidly disconnecting and connecting calling party’s telephone line.
So Pressing a single key (such as '4' ) will send a sinusoidal tone for each of the two frequencies (770 and 1209 hertz (Hz)).levers inside keypads activate two contacts and at the receiver ,it transmit to decoder and decode the pressed key value..
When transmitting signal strength of pair of tones must be below than +1dbm.And at the inter-digit interval any leakage of these tones must not exceed -55 dbm .And DTMF signaling hold standards for 50ms tone and 50 ms space. So DTMF works with above mentioned characteristics.
Relay Switches
The purpose of using Relay switches is on off electronic devices according to channels output from 8870.It has allowed controlling a high-current electrical load with a low-current electrical ‘signal’. Similarly In4 lead/pin SPST relay, as shown in figure, left coil is not powered and the right one is powered. This is how actually relay works as a switch.
PIC 18F452
Even DTMF decoder has the ability to manage those relay switches, a processing IC needs to take actions intelligently. It means switch on and switch off function can manipulate via a processor. And also further develop can manage by a processor too. Therefore Microchip PIC 18F452 has much needed Memory, functions and communication methods required for BTS Monitoring System.
In PIC18F452, it has used Micro C to program the PIC, 18F452 has compiler friendly development environment, 256 bytes of EEPROM, Self-programming, an ICD, 2 capture/compare/PWM functions, 8 channels of 10-bit Analog-to-Digital (A/D) converter, the synchronous serial port can be configured as either 3-wire Serial Peripheral Interface (SPI™) or the 2-wire Inter-Integrated Circuit (I²C™) bus and Addressable Universal Asynchronous Receiver Transmitter (AUSART). All of these features make it ideal for manufacturing equipment, instrumentation and monitoring, data acquisition, power conditioning, environmental monitoring, telecom and consumer audio/video applications.
Implementation
Due to using various technologies, circuits, programs they must have a connection between each other. In Implementation part it discusses about circuit designing, programming and tools were used for development. Exceptional attention has gone to PIC18F442 and its programming. Circuit designing also took a part in Implementation, but in this section it is going to describes briefly about how to use processor for the system needs.
In PIC programming we can use Assembly or C as a programmer language. There we have to configure registers at the microcontroller and also the input outputs, interrupt handling methods and other values at the micro controller .Due to easy development; here it uses “C” as the programmer language. Then the c compiler and hex tool kit have used for code the PIC by used the c program.