An LED throwie is a small LED attached to a coin battery and a rare earth magnet (usually with conductive epoxy or electrical tape), used for the purpose of creating non-destructive graffiti and light displays.
LED Throwies were devised by James Powderly and Evan Roth working together at the Graffiti Research Lab during a fellowship at Eyebeam OpenLab in 2006. The technology, like everything from the OpenLab, is open source and in the public domain. LED Throwies were designed as a new kind of graffiti art to be used on ferromagnetic surfaces like steel. Part of GRL's original campaign involved distributing throwies to a group of people, who were then encouraged to throw them onto a metal sculpture called Alamo, located at Astor Place, Manhattan, New York City.
The following are some of the modifications that have been applied to throwies:
- Clay, or another sticky, putty-like substance has been added to create a "stick-anywhere" Throwie.
- Throwies have been made with Velcro instead of, or in combination with, a magnet.
- Adding an on/off switch or a pull tab can prolong battery life.
- Flashing LEDs, effectively blinkies, can also improve battery life.
- More than one LED can be arranged around the battery.
- To achieve better light distribution, some have ground the top off of the LED so that the light is more diffused.
- Photoresistors have been used to limit or turn off the circuit in the throwie when light shines on them, which can extend battery life dramatically.
- Chirpies are another variation on the theme, incorporating a piezoelectric transducer and an alternating circuit, although this device is more controversial.
- Magnets can be replaced by small piece of styrofoam sealed with wax, and throw into pools, bathtubs, or other enclosed water areas as Floaties. Use of Floaties in lakes, streams or oceans is strongly discouraged for environmental reasons; lithium batteries are prone to leakage in water; Floaties are more difficult to collect than Throwies; and marine animals may eat the Floaties.
- Flyies are throwies carried as a payload on helium balloons.