I have tried to read upon Arrays and I'm guessing will have to start reading on variables too.
And almost certainly, many more things also.
is it safe to say that if I do use 25 shift registers...then I'm probably going to have an extremely long code,
Not really. You use arrays, loops and functions, anywhere there is repetition.
all LEDs turn on except last shift register, than my programs going to look like
digital write (mod 0-23, HIGH;)
Then if I want to turn those off, and have the last 3 turn on, it would go something like
DigitalWrite (mod 0-23,Low); DigitalWrite (mod 24, High)
No.
Because I don't think I have seen a program I understand that actually isolates one pin in a vast grouping of pins that uses shift registers.
Its all been like a matrix that has a flow to it, and that's not really what I want to do where everything is like a wave.
Don't know about the matrix and wave business, but there
are programs that do just this, it's just that it is difficult to find the correct search terms.
Simply, I just want to be able to turn on any LED at will.
Not using them all, but #92 turn on.
number #102 turn on when #92 turns off
kinda thing.
I think you need to make a habit of reading previous answers.
I explained this to you in
another post.
To use shift registers - and the MAX7219 is the proper way to do it in this case; four chips makes
vastly more sense than 25 - you have a copy or
image of the LEDs in an array. To change a given LED, you calculate where it is in the array - led number 102 is the sixth bit in the 13th byte of the array - and switch that on or off. You then (after making
all the changes necessary for various LEDs) call the single function that reads the
whole array and writes it to the shift registers. When it finally issues the latch signal to the registers,
all the LEDs adopt the new pattern with whatever changes you have made in the array.
{In fact, with the MAX7219, it is possible to change
only the 13th register byte, but it is not sufficiently quicker to make it worth the bother.}