PHOTOCHROMIC EGGS: not for breakfast

Photochromic paint is quite nifty – under exposure to light of the best wavelength, it’ll modification colour. This provides everything type of applications for short-term displays.  [Jiri Zemanek] chose to apply photochromic paint to an egg, utilising it to produce stroboscopic patterns with the assist of a laser.

Patterns for the egg are produced in MATLAB. A discovery STM32 board acts as a controller, taking care of the laser scanner as well as a stepper motor which rotates the egg. A phototransistor is utilized to sync the position of the laser as well as the egg as it rotates.

The photochromic paint used in this job is triggered by UV light. To energize the paint, [Jiri] harvested a violet laser from a Blu-ray player, fitting it to a scanning assembly from a laser printer. instead of scanning the laser across an imaging drum, it is instead scanned vertically on a turning egg. Patterns can then be drawn on the egg, which fade over time as the paint provides up its kept energy.

[Jiri] exploits this by composing a range of patterns onto the egg, which then animate in a way similar to a zoetrope – when visualised under strobing light, the patterns appear to move. There are likewise a few holiday messages shown for Easter, making the egg all the much more suitable as a billboard.

If you like the concept of drawing on eggs however are put off by their non-uniform geometry, inspect out the Egg-bot. video below the break.