A brief descriptionBlock DiagramMethodologyKey objectivesUses of the project
My project is a Scrolling (Moving) Message Electronic Display Board which displays the messages received as SMS or GPRS Packets. Public can send flash information from Mobiles or PCs to displays for instant viewing. Displays are designed to quickly display large amounts of information in the liquid crystal display.
Based on the principle of serial communication in collaboration with embedded systems. This project is an implementation to the idea of the wireless communication between a mobile phone and a microcontroller. It uses: a) A moving message display, which will be used as the digital notice board b) A GSM modem, Motorola C168 , which is the latest technology used for communication between the mobile and the embedded devices. c) Microcontroller, ATMEL AT89S52
User wants to display a messageUser sends the message in his mobile defining the messages and then the password of the system to the number of the subscriber identity module (SIM) which is inserted in the display system MODEM.
The GSM modem receives the SMS. TheAT commands are serially transferred to the modem through MAX232. The microcontroller will read the message from serial headphone andverify for the password, if the password is correct then it will start displaying the messages in the display system
1. Programming of the mobile phone with AT (Attention) command sequence2. Interfacing the programming chip with the personal computer3. Interfacing the programmable chip with the electronic board display4. Interfacing of the mobile phone with the programmable chip5. Sending messages from the remote phone to the electronic board
GSM (Global System for Mobile communications: originally from GROUPE Spécial Mobile) is the most popular standard for mobile phones in the world. GSM differs from its predecessors in that both signaling and speech channels are digital, and thus is considered a second generation (2G) mobile phone system. Most 2G GSM networks operate in the 900 MHz or 1800 MHz bands. The modulation used in GSM is Gaussian minimum- shift keying (GMSK), a kind of continuous- phase frequency shift keying.
The SIM is a detachable smart card containing the users subscription information and phone book. It is an integrated circuit that securely stores the International Mobile Subscriber Identity (IMSI) and the related key used to identify and authenticate subscriber on mobile telephony devices.
The programmer used is a powerful programmer for the Atmel 89 series of microcontrollers that includes 89C51/52/55, 89S51/52/55 and many more. It will Program, Read and Verify Code Data, Write Lock Bits, Erase and Blank Check. All fuse and lock bits are programmable. Major parts of this programmer are USB Port, Power Supply and Firmware microcontroller. Serial data is sent and received to this programmer through the USB connector. Programmer comes with window based software for easy programming of the devices.
Tentative model to beemployedMain Circuit BoardTechnical Specifications
ADVANTAGES LIMITATIONS This prototype has facilities Currently the main work to be integrated with a that has been done on this display board thus making proposed system is through it truly mobile. serial port to the computer but not wireless. The SMS is deleted from the phone each time it is read, thus making room for the The major constraints next SMS. incorporated are the use of ‘*’ as the termination The systems need not be character of the SMS and reprogrammed to display the display of one SMS as at new messages because it is a time. wireless. These limitations can be Communications between removed by the use of the subscriber and the base higher end microcontrollers station can be encrypted. and extended RAM.