Come up with a simple application using digital or analog input and digital output.
When it's time for bed, rest your phone here for an instant night light!
Materials & Tools
Book Board or Cardboard
White Card Stock
1 10k Ohms Resistor
1 220 Ohms Resistor
Female-to-Male Jumper Wires
Power for the Arduino (I used my laptop via USB)
Ambient light certainly impacts input readings from the photoresistor, even when covered by the card stock. This device as is needs to be calibrated for each new lighting situation.