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bs2-man
02-13-2010, 11:45 PM
i want to drive a 3x3 led array with a basic stamp. ill just make itĚdo some little annimations.

allanlane5
02-13-2010, 11:56 PM
Okay, that's 9 LED's -- you'll probably need at least a ULN2803 Darlington Array to drive that much current, the BS2 won't do it on its own.
And you'd probably want a 74LS164 serial to parallel latch to reduce the number of I/O pins needed.

Mike Green
02-14-2010, 12:01 AM
If you limit the current to each LED to something on the order of 4mA using a 1K series resistor, you can drive the LEDs directly using 9 I/O pins. The "What's a Microcontroller?" tutorial shows how to connect a single LED to an I/O pin.

You can also drive the LEDs as a multiplexed matrix where you drive only one LED at a time, but use more current and drive them fast enough so that "persistence of vision" takes place and it looks like several LEDs are on at the same time.

bs2-man
02-17-2010, 07:44 AM
ok, thanks. say i use nine i/o pins, what about animations? i probably dont need help with it but if anyone has an idea...