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Library's collection Library's IT development CancelThe development of microprocessor/controller technology that is very
fast, makes it possible to implement many control applications, and often in one
control application we need more than one controller to handle some different
tasks. So between controllers should have a communication to keep the application
run in the right way.
If there are so many controllers that involved, the cabling which is the
connection media between controllers becomes more complex and complicated.
Meanwhile the development of RF (Radio Frequency) technology even not as fast
as the development of microprocessor, it also gives nuance to some of electronic
applications. So when the two technologies above are combined together, it will
create a communication that is effective and powerful.
In this final task the combination of those two technologies above is
represented by two controllers that is connected into peer to peer connection,
where as controller, microcontroller 80C31 which is the member of MCS-51 family
is being used. While air media (wireless) is used as communication media through
frequency modulation (FM) at comercial frequency band (88 MHz - 108 MHz).
Before being transmitted by FM transmitter, data is encoded using FSK (Frequency
Shift Keying) method, with mark frequency (for digital data '1') 2400 Hz dan
space frequency (for digital data '0') 1200 Hz.
Matrix keypad 3X4 is used as data input module and to visualize data that
already received, LCD 16X2 characters is being used. While to simulate the
control action, an actuator module that is built from 8 LEDs is being used. The
condition of those LEDs (ON or OFF) will be controlled by each controller.
After doing some stage of test, the result is that the system can work well
with 500 bps maximum transfer rate. Unfortunately the system can't communicate
in long distance, but it can be overcomed by choosing or designing a good FM
transmitter.