Most persistence of vision projects I have seen involve moving a strip of leds fast enough that our eye perceives it to be an image. Make magazine has covered many projects of this type.
Jens Wunderling, a student of the Digital Media Class at UDK Berlin, has created at second glance, an alternative approach to POV. Instead of moving the LEDs, Wunderling has them fixed in position, but plays with saccades (our eyes never look straight, but always make fast tiny movement around an area).
So if you happen to glance past the work, you may notice something unusual. On second glance, if you shake your head, you will be able to clearly see the symbol. Created as a “guerilla messaging device, made to place hidden critical messages within the abundant medial environment in the city”.
Developed using Arduino and Processing, the source code of which is available on his site, and 32 ultrabright LEDs.
More from Jens Wunderling
loopArena at Cybersonica, Building a multitouch, loopArena multitouch