LED-BASED MESSAGE DISPLAY MINI PROJECT

LED-BASED MESSAGE DISPLAY MINI PROJECT:
This LED-based message display is
built around readily availble, lowcost
components. It is easy to fabricate
and makes use of 3mm red LEDs. A
total of 172 LEDs have been arranged to
display the message “HAPPY NEW YEAR
2004.”
The arrangement of LED1 through
LED11 is used to display ‘H’ as shown in
Fig. 1. The anodes of LED1 through LED11
are connected to point A and the cathodes
of these LEDs are connected to point
B. Similarly, letter ‘A’ is built using LED12
through LED21. All the anodes of LED12
through LED21 are connected to point A,
while the cathodes of these LEDs are connected
to resistor R8 (not shown in the
circuit diagram). Other letters/words can
also be easily arranged to make the required
sentence.
The power supply for the message display
circuit (Fig. 2) comprises a 0-9V, 2A
step-down transformer (X1), bridge rectifier
comprising diodes D1 through D4,
and a filter capacitor (C1). IC 7806 (IC1)






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