Problem: I've made a circuit consisting of an 8x8 led matrix, which uses all of the digital pins on the Arduino UNO board, and I want to add an LED too it.

I tried looking around the internet but so far, I have not seen any solution on how to use a simple LED with no digital pins to spare.

So I ask, is it possible to connect an LED with no leftover digital pins? I just want to be able to turn the LED on and off.


1 Answer 1


Just found this:


Turns out you can use the analog pins of an Arduino UNO using this:


You just have to list it as an analog pin. Seems to be working, don't think there are any downsides, as far as I see.

  • Yup. Though make sure you see the note there by CrossRoads regarding A6 and A7 on SMT based UNO (and other SMT 328P Arduino).
    – timemage
    Commented Dec 28, 2020 at 1:41
  • 1
    In a couple days time you'll be able to accept your own answer, and probably should assuming someone else doesn't provide another you like better.
    – timemage
    Commented Dec 28, 2020 at 1:44
  • Ok, yeah I'll do that later, unless I get a better answer as you said.
    – John Doe
    Commented Dec 28, 2020 at 1:47

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