Light-Dependent Resistor Camera

As shown in the video below, photoresistors (also known as light-dependent resistors, or LDRs) can sense darkness, lighting up a single LED in a voltage divider setup. It’s an interesting concept on its own, but if you were to arrange a number of LDRs in an array, it should then be possible to make a very basic camera by feeding the voltage results to a computer.

Creator Electromechanical Productions actually built such a camera, arranging 48 LDRs in a 6x8 grid. Voltages from each one are fed to an Arduino Nano’s analog inputs with the help of six SN74HC4051N multiplexers. The Arduino/multiplexers scan through each set of 8 LDRs over and over, using digital outputs to properly address the sensors for data collection.

The Arduino passes this data along to a computer via serial, where it’s processed using Python and the Python Image Library (PIL). Results are very low resolution and black and white, though it’s hard to be disappointed with a device labeled as “the worst digital camera of all time ever."

It its defense, Electromechanical Productions does demonstrate the camera's functionality, showing how the image lightens with a flashlight in front, with a pen added to form a diagonal line, and with a folded triangle to show a solid shape. Of course, things could be improved by adding more LDR pixels, using a motorized setup to move and track changes, or perhaps a lens of some type. For now it’s quite the interesting technology demonstrator!