How to connect many buttons and diodes to Raspberry Pi 3 b+?

Question

Raspberry Pi

There is a need to connect the following things to the raspberry:
~ 10 buttons (remove the signal is pressed / released)
~ 3 rotary controls (like a volume control)
~ 3 three-position switches
1 rotation sensor (not sure what it is called, like a volume control, only it can rotate endlessly in one direction, you need to consider the speed)
~ 5 LEDs
The number of connected elements may change in one direction or another.
As I understand it, it is usually supposed to be connected via GPIO, but the number of pins is limited there. What are the options?

Answer 1

> ~10 buttons (take a signal pressed / released)
Matrix keyboard, for example.
> 1 rotation sensor (I'm not sure what it's called, like a volume control, it can only rotate endlessly in one direction, you need to count the speed)
An encoder or an encoder is called.
> ~5 LEDs
You can hang on i2c PCF8574 and drive diodes through optocouplers.

Answer 2

You would first practice connecting each of these elements to the Raspberry Pi separately. And then you don’t know their names, but you already want everything at once and a lot. Learn everything gradually. Then you will find out, for example, that raspberries do not have their own ADC and just like that, without an additional circuit, 3 potentiometers (your ~ 3 rotary controls (like a volume control)) it makes no sense to connect that even with ordinary buttons due to the fact that they are "in quite different places "You can run into pitfalls.