Analog buttons in a digital world…

Ok, I hate this analog to digital stuff. I just can’t get it to work. I should have written down the EE’s scribblings, too.

As I said in talking about my remaining inputs I need a total of 11 pins (8 inputs: 3 buttons, 2 rotary encoders (each uses 2), 1 rotary encoder button and 3 outputs: the button LEDs) and I have just that many, with no expansion room.

But there are other things I may need pins for, like a possible idea for the radiation gauge or using EL wire/sheet for the pipboy’s light…

I happen to have a SIPO (Serial-In, Parallel-Out) 74HC595 Shift Register IC that will let me control the 3 LEDs with 3 pins (thats a wash, I know) but would give me 5 more outputs if I needed them.

There are also PISO (Parallel-In, Serial-Out) 8-bit shift registers that would let me combine the 8 inputs into 3 pins as well, or if I needed I could daisy chain a second shift register to get another 8 inputs.

Apparently there are also programmable shift registers that do both SIPO and PISO, but they appear to only be SPI (Serial Peripheral Interphace) and the Nano MP3 shield appears to be using those pins. I wonder if its only those pins?