Development Of An Embedded System

This project is aimed to design a system to develop an automatic unmanned railway gate by using GSM technology. A GSM modem provides the communication interface. It transports device protocols transparently over the network through a serial interface. A GSM modem is a wireless modem that works with a GSM wireless network. This GSM Modem can accept any GSM network operator SIM card and act just like a mobile phone with its own unique phone number. Advantage of using this modem will be that you can use its RS232 port to communicate and develop embedded applications. Applications like SMS Control, data transfer, remote control and logging can be developed easily. The modem can either be connected to PC serial port directly or to any microcontroller. Railways, being the cheapest mode of transportation are preferred over all the other means. When we go through the daily news papers, we come across many railway accidents occurring at unmanned railway crossings. This is mainly due to the carelessness in manual operations or lack of workers. In order to overcome these dangerous problems we in this project came up with a solution for the same. Using simple electronic components and a wireless communication technique we have tried to automate the control of railway gates. Use of embedded technology makes this closed loop feedback control system efficient and reliable. AT89C51 microcontroller is the heart of the circuit as it controls all the functions. This project is designed in such a way that a GSM modem will be interfaced to the controller through serial port interface along with the DC motor through voltage driver IC L293D. The railway gate is connected to this motor. The microcontroller will be programmed in such a way that some predefined messages will be assigned to the controller for controlling the motor in different directions i.e. opening and closing of the door. When ever the user wants to control the gate, he has to send predefined messages to the modem. When the modem receives data (SMS), it will intimate the same to the microcontroller. Now, it is the job of the controller performs the predefined task of controlling the gate in clockwise or anticlockwise in accordance with the message received from the modem. A 16X2 LCD will be interfaced to the controller to display the status of the railway gate. This project uses regulated 5V, 500mA power supply. 7805 three terminal voltage regulator is used for voltage regulation. Full wave bridge rectifier is used to rectify the ac output of secondary of 230/12V step down transformer.