I am making my own "7 segment LED driver". I know there is a lot of examples on the internet, I just want to try my own. But I have a piece of code that does not work and I don't know why. Can somebody explain to me why it is not working?

When I put in this, it works:

digitalWrite(pins[0], one[0]);
digitalWrite(pins[1], one[1]);
digitalWrite(pins[2], one[2]);
digitalWrite(pins[3], one[3]);
digitalWrite(pins[4], one[4]);
digitalWrite(pins[5], one[5]);
digitalWrite(pins[6], one[6]);

So of course I tried using for():

for (byte i = 0; i >= 6; i++)
    digitalWrite(pins[i], one[i]);

And this does not work. But why? I think it should. Btw. pins is const byte array and one is const bool array.

Thanks in advance for any suggestions!

  • I don't see why it shouldn't work; what happens instead? Oct 14, 2015 at 19:23
  • The seven segment display stays off, nothing lights up; but i am sure i have it connected right, because the first code works. But the compiler doesn't give any errors....
    – user72028
    Oct 14, 2015 at 19:42

1 Answer 1


You've written the for loop incorrectly.

for (byte i = 0; i >= 6; i++)   <-- ERROR HERE
    digitalWrite(pins[i], one[i]);

That first line should be for (byte i = 0; i <= 6; i++). i begins at zero, which is less than six, and the loop only runs while i is greater than 6.


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