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I am working in a book store and I have the task of making an indication of a book place in the Library Cupboard with LEDs. I need to control about 300 LEDs with Arduino. What is the optimum way to do this task?

I think I can't use shift registers because I need to power each LED separately from the others.

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  • \$\begingroup\$ Describe a bit more what your goal is. \$\endgroup\$ – Ignacio Vazquez-Abrams Sep 7 '14 at 21:18
  • \$\begingroup\$ lets say if there is a book in a specific Cupboard and specific row in that cupboard , what i need to do is to make a led on the cupboard flash on and a led on the row flash on too \$\endgroup\$ – Abdelrahman Elshafiey Sep 7 '14 at 21:22
  • \$\begingroup\$ With latched shift registers (such as 74HC595), there is really no percievable difference from powering each one individually. Although program will be less efficient because it will have to shift out all 300 bits at every update. \$\endgroup\$ – venny Sep 7 '14 at 21:40
  • \$\begingroup\$ @venny so i can power each led individually using latched shift registers ? \$\endgroup\$ – Abdelrahman Elshafiey Sep 7 '14 at 21:45
  • \$\begingroup\$ If by power individually you meant to make one (or more) of the 300 blink, then the answer is yes. \$\endgroup\$ – venny Sep 7 '14 at 21:53
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I think I can't use shift registers because I need to power each LED separately from the others.

That sentence makes no sense. Shift registers, and LED power, are two separate things.

Your best bet is to use a chain of constant current sink LED driver shift registers, such as the STP16CP05.

If you want to get more decentralized and rugged you could think about grouping the LEDs together into small chunks, each chunk with its own microcontroller, and use something like RS-485 to create a backbone communication link between them all with a master device sending out the commands to tell slaves to turn LEDs on and off. That would be a better solution in a noisy industrial environment. Libraries are seldom noisy though ;)

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  • \$\begingroup\$ i saw couple of videos of people controlling several leds with shift register but they make the led power in a constant way , so i think what i said about SR is not wrong \$\endgroup\$ – Abdelrahman Elshafiey Sep 7 '14 at 21:27
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    \$\begingroup\$ Look at the LED type WS2811/2812. individually addressable LED's. \$\endgroup\$ – MatsK Sep 7 '14 at 21:31
  • \$\begingroup\$ I agree with Majenko. "Separately powered" Please elaborate, perhaps a drawing or a url to the examples you mentioned. \$\endgroup\$ – MatsK Sep 7 '14 at 21:34
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The quickest way I know to throw together a quick prototype with dozens/hundreds/thousands of individually-controllable LEDs is to use a Digital LED Strip with an Arduino and an appropriate power supply and a few wires.

(These 2 kinds of LED strips already have the shift register chips built into the strip).

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