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LED Lights

A project log for Portrait Plotter

An interactive installation that takes your photo and paints it on paper.

Christian WaltherChristian Walther 04/24/2018 at 13:360 Comments

This is one of the two LED lights as it was made in December: NeoPixel strips (left over from my LED panel project) mounted on gray cardboard. Power and signal is delivered over a ribbon cable where 3 wires each are connected in parallel for the power lines, empirically determined for an acceptable voltage drop at maximum current. Some of the red and blue power wires between the strips are redundant in order to get a more even voltage distribution under load, however I did not measure whether that was actually needed.

The LEDs, among other things, are controlled by an Arduino Uno that is also connected to the computer by USB-serial. I would normally use something smaller, but I had a couple of these lying around. The Arduino does all the interfacing between the computer and the various electronic parts:

There are conflicting opinions on whether it is safe to power an Arduino Uno through its 5V pin while it is also connected to a computer by USB, so what I did was instead power it by USB from a powered USB hub, which in turn is powered from the 5V power adapter that also powers the LED lights. This way, the hub takes care of not feeding power back into the computer.

Now, for the final setup, I enclosed the LED lights in a sandwich of more cardboard and paper parts with cutouts for the internal components (cut on the Curio), an MDF back plate, and an acrylic front plate (lasercut). With the neck of the acrylic part, the lights are hung from a circular curtain rail that allows them to be moved 360° around the subject.

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