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How many outputs is too many?


#1

Lets say GHI offered a module specifically made to control LEDs (Don’t we all love LEDs!) where the module took SPI from the mainboard and gave you digital output (shift register basically) then how many IOs will be too many? Do you see yourself using 100 outputs, 200…1000!!! The outputs are rated 20mA so standard LEDs can be wired directly but you will need transistor to wire large LEDs.

Remember that you will be wiring each LED so keep that in mind when you give a number back. Also, note that you can wire things in a matrix form and now 16 pins will give you 8*8 LEDs 64.

LED cube anyone? :wink:

Time to remake this using gadgeteer


#2

Sure! :smiley:


#3

Aah this is coming at exactly the right time! I’m making a LED wall for my daughter for her birthday.

My wish list would be:

  • RGB addressable.
  • Daisy chain modules. I’d say either a string of 8, expandable with another 7 strings or a block of 8x8.
  • Multiplexed to save power but it must hold it’s own state and not need a software refresh loop.

I was wondering if an LCD controller chip could be used for this.

What chipset do you have in mind? A specialist chip (easy) or a bunch of shift registers with discrete components (cheap).

After seeing the video on troll series circuits it got me wondering if one could use inductors to address the Leds instead of purely digital. Each column might have a filter at a specific resonant frequency to address X and each row has a digital pin. It means one could expand very wide with few pins.


#4

You can never have too many LEDs!