Project: built a 7x10 led matrix module
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Features of project: 7x10 leds matrix module implemented with two 7x5 modules. Direct connection without wires to 14 pin LCD connector, for Bolt 18F2550 and Bolt v.Lite. The module may be connected to a standard LCD interface, so your system may work either with LCD, a seven segment display or a 7x10 led matrix module. 4 test and application programs are included: shows two numbers, a decimal counter 00 to 99, to display a message with scrolling in columns and to display a random number.
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The
module uses the
time multiplexing technique
to
turn on the LED
patterns and
form letters, numbers and graphics. Complete libraries are provided with patterns to show numbers, letters, symbols and graphics. in the picture at left a graphic character is shown. 2 graphic characters are provided in libraries: an arrow and a heart. Library with complete set of patterns is: Please consult the table shown below to see complete set of characters available in this library. |
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The design of the circuit is based on two 7x5
GMM-12057ASB
modules.
The
14-pin connector
is compatible with signals
of
Bolt 18F2550. The operating principle of the double matrix of 7x10 uses a technique of time multiplexing to display characters on the display. RA1 and RA2 are used to control a 4017 Johnson counter while RB1...RB7 output the character patterns in the columns of LEDs. 10 BC337 transistors are used to activate each column. The transistors are triggered one a a time by the Johnson counter. Electronic diagram here: matrix7x10.pdf
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Module may be connected directly to the 14 pin LCD port, either to Bolt 18F2550 system, or Bolt v.Lite module as shown. 4 application programs available here:
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