Re: LDR pulldown resistor value ? For line tracking Robot
The value of the resistor is not very critical. Especially since with RV1, you can set the threshold according to the resistor you used. If the contrast between blue and white is adequate, you will have no problems.
A good starting point is to choose the resistor equally to the average value of the LDR resistance, then you will have maximum sensitivity. So
[ LDR_resistance (white line) + LDR_resistance (arena) ] / 2
will certainly do.
But the value is not very critical, since you can adapt the threshold with RV1.