Apologies in advance for probably missing a lot of things. I'm pretty new to electronics.

I'm building a 96(12X8) led (monochrome ultra bright, white) multiplexed array, driven by an Arduino nano. Any one of the leds can be on at a given time.

  1. I tested one of the LED's and when configured and ran though Arduino's blink program and it works fine and the LED is lit bright.
  2. Next i had to try out the same LED with a 595, so i used this tutorial for reference.
  3. I accordingly hook up the LED and it's working fine, but the brightness is significantly low.

And that brings me to the question, whether i should charlieplex and build the whole network, or is there a way to improve the LED brightness while using 595's?

Thanks for your comments and suggestions.


I love charlieplexing, perhaps too much.

Do you mean 'any one' or 'only one' LED on at a time?

With a 595 pin per LED, you can drive them continuously at high current, there is no reason why they should be dim. You can drive any combination of LEDs at full power.

With charlieplexing, if done niavely, then the best duty cycle you get is 1:N when there are N LEDs in your array, which is a huge brightness reduction. If 'only one' LED is to be on at any time, then it can be driven at full power.

If you a bit more clever with charlieplexing, then you can approach a multiplex of 1:sqrt(N), to allow any combination of LEDs, or a few carefully chosen restricted combinations of LEDs at full power.

You can regard charlieplexing as a conventional non-square multiplex with each column driven by an unused row. However, in this mode, if driven direct from the microcontroller pins, the current is limited to Ipin/number_of_columns. If you use a high current column driver, that rather defeats most of the saving of a charlieplex.

  • \$\begingroup\$ Thanks for the comment, I am planning to turn any 1 LED on at a time based on the serial communication I get from the serial port. \$\endgroup\$ – S4nd33p Apr 25 '16 at 10:39

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