There is something I don't understand. Many tutorials say that by regulating an LDR or potentiometer you can regulate the analog value. Arduino guide says it is done by converting voltage to this value between 0 and 1023. The thing I don't understand is the fact that resistors don't regulate voltage but current. So can someone explain to me how is it that apparently the voltage is controlled by resistance?
It's not done with one resistor, but two, forming a voltage divider: https://learn.sparkfun.com/tutorials/voltage-dividers
So is the other resistor in the arduino? Because you can get an analog value just with one pot/LDR.
A potentiometer is an adjustable voltage divider. It has both resistors (actually only one resistive element but with the wiper dividing it into two resistors).
As for the LDR, I don't agree. I've only seen them used with another resistor. Maybe you can provide a citation for your assertion.
Of course the microcontroller on the Arduino does have internal pull-up resistors, which you can turn on/off via pinMode().
An LDR definitely needs a second 'fixed' resistor, but that can be the internal pull up resistor of the pin. Leo..