Home Chapter 17 Maxuino/Arduino photo resistors

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Maxuino/Arduino photo resistors

Photoresistors are variable resistors, which react to the number of photons present in the environment. They are most reactive to frequencies of light with sensitivity in the region of 500-600 nanometers (nm). You can purchase photocells here.

You can put a photoresistor in a tube to allow it to be even more sensitive to shadow. A nice article on photocells can be found here.


various light resistors


Hooking up a photo sensor with a resistor to the Arduino.

If you did not want to have to build your own some come with the 10 K Ohm resistor as already part of the board.

Keyes KY-018 Photosensitive Resistance Sensor Module For Arduino.

As with all photosensors they can be used for wide pan sensing to sense shadows. We see them in solar garden lights - lawn detectors - clocks- musical gift boxes - mini-night lights - light switching toys on as well as a variety of light control applications: Working voltage: 5v
PCB size: 1.5 x 1.9cm.

Keyes Photo resistor module. 


The code for the analog input for the photoresistor is the same as that for the potentiometer.

Copyright Ken Rinaldo