I still have confusion about multiplexing and shift-registers..
A shift register is essentially a demultiplexer. You feed serial
bits into the shift register, and the shift register isolates &
outputs the bits depending on their position in the data stream.
Perhaps you mean to say matrixing... For example, with 12
outputs you can create a 6x6 matrix to control 36 LEDs or
relays. 36 transistors or data lines from the matrix would be
trickier because you loose your common ground line. I don't know
what specific transistor to use, I need two things: - Minimal
noise - Minimal costs Noise shouldn't be an issue in a switching
application. But the signal-to-noise ratio depends on what kinds
of "signals" you're working with. ...to build something similar
to a digital potentiometer... Before you get too deeply into
this, I'd recommend experimenting with 2 or 3
transistors/resistors to test-out your concept. you can hard-
wire the transistor inputs, or use pushbutton switches if you
want to test it without programming t