my project using 500 LED :idea: , need to switch them on/off individually using PC/laptop. :shock: please help

 

Build this and make a series of LEDs of about a 100 each.

This website just shows hot to make 1 input but you could add more easily.


http://www.electronic-circuits-diagr...tersckt1.shtml

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Here's the easiest way (I think):

Make a matrix (24 by 24 = 576 LEDs). Then, say LED #10 should be turned ON. If it's located on "input" 2 and "output" 5, then make "input" 2 High and "output" 5 Low. Keep other "outputs" high and other inputs "low".

You'll need to use 6 8-bit multiplexers (3 for "input" and 3 for "output"). Their addresses will be controlled to the PC parallel Port, so you'll need:
3 outputs for address selection on "inputs"
3 outputs for address selection on "outputs"
2 outputs for chip selection on "input" (1 out of 3 chips should be selected)
2 outputs for chip selection on "output"

After that, you can connect (in parallel) the corresponding address selection pins on 3 "input" and "output" multiplexers. The chip selection will tell to multiplexers which one the PC is controlling.

The LEDs should have their + connected to "input" multiplexers and - to "output" multiplexers. The Input of each multiplexer should be tied to Vcc.

Good Luck,
TI|CP

Attached Images

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U may use a relay that connected to parallel port (D0-D7) to ON/OFF the LEDS. Get some info from http://www.geocities.com/bagtool/parallel_basic.html

free 8)

 

Relay? that would be expensive and slow...

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