The Reactive Lantern started off as an idea for an audio-reactive lantern that my then four year-old son could take to a night event in the park during the 2012 Mid-Autumn Festival.
The tessellated shell was designed in OpenSCAD modeling software, and then printed on my scratchbuilt 3D printer. And the tree branch was contributed by my son.
The reactive element of the lantern was accomplished using a simple audio op-amp circuit, with a tiny electret microphone implanted on the end of the tree branch. This circuitry allowed the LEDs mounted inside the lantern to flicker and pulse to the ambient sound of the surroundings. It is powered by a 9V battery.
The event organiser saw the lantern and let my son lead the lantern procession, which made him very happy. He lost interest in the lantern soon after the procession, but I am still hopeful that a 2013 update can rekindle his excitement.