Light Writer is a persistence of vision application for the iPhone. Essentially it’s a tool for using your iPhone to paint with light…and it’s pretty fun to play with.
You will most likely need a camera to actually be able to see the effect. A slow shutter shot will allow the full message to be displayed and your movements while displaying it can further enhance the effect:
You simply enter your message, choose your color(s) and then move the iPhone infront of the camera – it’s accelerometer will start displaying the message once it detects movement. It can take a lot of tries to get it to work right…I’ve got lots of shots of a blur of light rather than the message because I was moving the iPhone too fast.