MEKACI:
- The serial readings we are seeing in the serial monitor which represents the voltage changes of the analog input (that are converted analog voltage between 0-5V into digital values in the range of 0-1023) where we connect our LDR on Arduino, right?
Yes, the value returned by analogRead() is directly proportional to the voltage on the analog input pin.
MEKACI:
2) The resistor we connect to LDR affects the measurement values in the serial monitor too, right?
Yes.
MEKACI:
Then, which resistor is best to use on LDR?
Measure the resistance of the LDR in your normal room lighting. Use a resistor near that value.
MEKACI:
3) What happens if I don't put a resistor to LDR that it shortly burns out or damages the LDR ?
The input will always read 0 or 1023. The LDR and Arduino will not be damaged but you won't get any useful values.
MEKACI:
4) This is simple distance calculation equation (X = V.t). SO, in our case, how can we find the distance between LDR and the Light Source?the speed of light = 299 792 458 m / s ,and let's say the distance between light source and LDR are 10cm then I can find the time. However, how to find the distance as using the analog readings of LDR on the serial monitor in Arduino ?
The LDR measures light intensity. Intensity of a point source of light drops with the square of the distance. Measure intensity at various distances in a dark room and interpolate.