JRL modded the MiniPov kit we sell in the MAKE store to hail taxi’s better in Singapore. Turn it on, choose the text and as you wave it around it spells words in the air…
“Immediately I had in mind an application for it which would be to hail a taxi in Singapore.
I have therefore taken the original hardware and schematics of the project (see here) but have modified it slightly by adding one additional switch between pin 11 of the AVR chip and ground and one 10K resistor between the same pin 11 and pin 20. Then I have written a different program to run the device which allows me to have 8 different texts and permits the usage of bold and inverse attributes.” – Link.
Source and binaries are on the site too, nicely done. Open source hardware begets fun like this.