23-07-2012, 01:19 PM
Wireless Notice Board Using LEDS
Wireless Notice Board Using LEDS.pptx (Size: 448.48 KB / Downloads: 39)
INTRODUCTION
The project aims at displaying the messages on the 8X8 DOT MATRIX LED using RF technology.
The objective of the project is to develop a microcontroller based display system.
It consists of PC, RF transmitter and receiver section, microcontroller and the display unit at the receiver side.
Any number of characters can be displayed using scrolling effect
RF TECHNOLOGY
Radio frequency (RF) is a frequency or rate of oscillation within the range of about 3 Hz to 300 GHz.
RF waves are electromagnetic waves which propagate at the speed of light
MICROCONTROLLER
Features of AT89S52:
8K Bytes of Re-programmable Flash Memory.
RAM is 256 bytes.
4.0V to 5.5V Operating Range.
Fully Static Operation: 0 Hz to 33 MHz’s
256 x 8-bit Internal RAM.
32 Programmable I/O Lines.
Three 16-bit Timer/Counters.
Full Duplex UART Serial Channel.
Watchdog timer.
Fast programming time.
Flexible ISP programming (byte and page mode).
PIN DIAGRAM
All ports are 8-bit open bidirectional I/O ports
Port 3 also serves the functions of various special features of the AT89S52, as shown in the following table.
Program Store Enable (PSEN) is the read strobe to external program memory
External Access Enable EA must be strapped to GND in order to enable the device to fetch code from external program memory locations starting at 0000H up to FFH.
XTAL1 Input to the inverting oscillator amplifier and input to the internal clock operating circuit.
XTAL2 Output from the inverting oscillator amplifier.
8X8 DOT MATRIX LED
A dot matrix is a 2-dimensional array of dots used to represent characters, symbols and images.
A dot matrix is useful for marking materials other than paper. In manufacturing industry, many marking applications use dot matrix inkjet or impact methods.
This can also be used to print 2D matrix codes, e.g. Datamatrix.
FUTURE ENHANCEMENT
Dot matrix range can be extended
RF range can be extended
Many displays can be added to single system
ADVANTAGES
Security is provide; program at transmitter has to match at receiver, there is no chance of getting data to other devices
Any number of characters can be displayed
Conclusion
It can be concluded that the design implemented in the present work provide portability, flexibility and the data transmission is also done with low power consumption
Design is done to meet all the specifications and requirements.
The user need not go to the black/green board to write the messages so that the employees/students come to know the issues of the institutions/offices.