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Topic: LED Driver (Read 708 times) previous topic - next topic

dansku

How many leds can I use with this circuit from  http://www.arduino.cc/en/Tutorial/ShiftOut
in the website, it shows up to two sets, but is there any problem of using more? what about the mA usage, will arduino support all that?

MysteriousAges

If you've got the LEDs on a different chip, you'll have to make sure that chip can source all the current nesseracy to drive the LEDs, not the Arduino. ;) You could also use transistors to switch the LEDs and you wouldn't have to worry about what the chips can provide for the most part.

John_Ryan

Quote
How many leds can I use with this circuit from  http://www.arduino.cc/en/Tutorial/ShiftOut
in the website, it shows up to two sets, but is there any problem of using more? what about the mA usage, will arduino support all that?


With the 595, there's only ever 8 LEDs on at a time.

http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1185507207/45#45

The code gets processed so fast, it "looks" like all the LEDs are on, so you can piggy-back as many 595's as you need, per the code in the link above :)

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