The photoresistor is based on light resistance, it will sense the light and will allow the microcontroller in this case Arduino to react and change the intensity of Led Diode. The photoresistor ...

For backlighting purpsoe, 5V dc supply is fed to the backlight pins BL1 and BL2 (also labelled as LED+/BL+ and LED-/BL-) through a suitable current limiting resistor (for instance, with a 100-Ohm one) ...

[Fjord Carver] brings together an RGB LED and CdS Photoresistor to make a color sensor. Those Cadmium Sulfide lights sensors usually have a very wide swing of resistance when exposed to varying lev… ...

He managed to build his own monitor using an Arduino. The trick of this build has to do with how the system works. The panel includes an LED light that blinks 1000 times for each kWh of electricity.