Experiments in Field Drawing on Vimeo The RFID pen maps out the fields surrounding an RFID tag.

RFID ("Ar-fid") chips represent an easy solution to tracking people or things. The chips are embedded in everything: cars, shoes, cell phones and clothing. Useful for retailers tracking inventory, but after the goods are sold the chips remain track-able. Buying chipped merchandise with a credit card links the RFID chip in the merchandise to your identity. RFID readers can be programmed to send an alert whenever your RFID chip is nearby.

Of course, you're a law-abiding citizen so you have no concerns about ubiquitous monitoring and surveillance.