Allochroous is a device that generates unique light projections fluctuating in shape and color depending on the input from a user. It is designed and built as an outcome of experiments with optics and light behaviour.
The project is designed as an installation piece open to input from the visitors. In the optimal case the device should be located facing to a corner of a room, projecting across 4 to 5 meters onto the wall.
The device works by getting the input from the four dials placed on the top cover, and projecting a beam of light generated by an LED unit through the custom made optics onto a projection surface. The intensity of red, green and blue channels can be controlled through the right three dials on the top. The far left dial is reserved for the frequency control. In action the device generates light in a strobing fashion depending on the frequency input.
Several different cylindrical lenses can be attached in the front cavity of the device. Unlike circular lenses which focuses light in a circular and uniform way, cylindrical lenses directs and focuses light on mostly a single plane, in this case horizontal, creating a wide projection effect. Another interesting effect with the cylindrical lenses is the splitting of the different color channels(dispersion). Normally an RGB LED produces a single combination of color depending to the intensity of each color channel, however in the case of the cylindrical lenses, the channels are dispersed on the vertical plane.
The lenses are cut from an acrylic sheet with a laser cutter and finished to an optical quality by hand. After gradual wet sanding with sanding compound the lenses are flame polished and wet buffered to finalize the surface finish.
The graphic below illustrates some of the different lenses.
The device measures 11 cm x 5.5 cm x 6.5 cm. The casing is made out of aluminum and finished by hand to give it a brushed aluminum look. As it’s intended for installation and should be turned on for long times, a fan is located on the backside of the device to dump the heat generated by the LED. However it is not a significant concern since also the casing is made out of aluminum which naturally acts as a heatsink. The device is controlled by an arduino inside and also has the extra feature of taking input from a jack connection to change the frequency according to the sound levels.