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1.0 INTRODUCTION
This project is based on GSM MODEM & PIC16F877Aµcontroller.
For doing this project we use some of the software like
 Embedded C for programming the application software to the microcontroller.
 Protel schematic software is used for designing the circuit diagram for this project.
 Express PCB software is used for designing the PCB for this project.
(Since PCB making is a big process and involves lot of machineries which are expensive, we are going to outsource this to the manufacturer.
Now a days every one need automation for their devices, so that these can be controlled remotely. A lot of methods are there to do this task. In our project we have selected SMS based device controller, which can switch ON/OFF any device remotely by sending a SMS. These type of device controller can be used in our houses & offices to switch ON & OFF appliances as and when required by just sending one SMS.
The big shops and shopping centers are using the digital moving displays now. In Railway station and bus stands everything that is ticket information, platform number etc is displaying in digital moving display. But in these displays if they wants to change the message or style they have to go there and connect the display to PC or laptop.
As every one is equipped with a mobile now a days, so it gives a great flexibility & cost effective solution to control the devices through SMS
1.1 COMPONENTS USED:
 Power Supply 5v DC - 7805
 Step Down Transformer - 12V/500mA
 Diode - 1N4007
 Capacitor - Electrolytic/Ceramic
 PCB - General Purpose Phenolic
 Microcontroller - PIC16F877A
 Crystal - 12 mhz
 MAX 232 - For Serial Communication
 GSM Transmitter and Receiver
 RELAY - For driving load
 RELAY Driver - ULN2803
 LED - Red Color for Indication
2.0 Microcontroller
PIC is a family of Harvard architecture microcontrollers made by Microchip Technology , derived from the PIC1640 originally developed by s Microelectronics Division. The name PIC initially referred to "Peripheral Interface Controller".
PICs are popular with both industrial developers and hobbyists alike due to their low cost, wide availability, large user base, extensive collection of application notes, availability of low cost or free development tools, and serial programming (and re-programming with flash memory) capability.
Microchip announced on February 2008 the shipment of its six billionth PIC processor.
2.1 Advantages
The PIC architectures have these advantages:
 Small instruction set to learn
 RISC architecture
 Built in oscillator with selectable speeds
 Easy entry level, in circuit programming plus in circuit debugging PICKit units available from Microchip.com for less than $50
 Inexpensive microcontrollers
 Wide range of interfaces including I2C, SPI, USB, USART, A/D, programmable Comparators, PWM, LIN, CAN, PSP, and Ethernet
2.2 Limitations
The PIC architectures have these limitations:
 One accumulator
 Register-bank switching is required to access the entire RAM of many devices
 Operations and registers are not orthogonal; some instructions can address RAM and/or immediate constants, while others can only use the accumulator