From Instructables user Djando:

After the amazing case to the dress that everybody sees in a different color, I decided to create a device that can easily find out the colour of an object.

To make the project more interesting, I considered making it communicate with a Lifx bulb. this kind of bulb can change color using its dedicated smartphone app or, as I did, using a Node.js application…

…The photoresists works similarly to our eyes as far as the answer to light is concerned: if the same object is illuminated by three different colors (red, green and blue), the photoresists receives three different answers in terms of wavelengths. The three answers will be calculated by the program and the result will be the color of the object.

Once acquired the value of the color, this will be sent to the lamp and the lamp will light on using the same color.

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