Here, a standard light-dependent resistor (LDR) is used as an analog input sensor and directs its output to the Serial ... GND to Gnd, and OUT to A0 of Arduino). See the Arduino & Processing sketch ...

[Gord Payne] has one with an elegant sensor ... reaching the LDR from the LED decreases as the pipe is bent, and with a simple divider circuit a voltage can be read by an Arduino.

This solar tracker system uses the Arduino ... A0 and A1 on the board. The “tolerance” variable is used for allowing a small tolerance otherwise the solar panel would be continously adjusting its ...