After building a USB magnetic stripe reader, [David Cranor] has found a way to fool a magnetic stripe reader using a hand-wound electromagnet and an iPod. The data on a card is read and stored on a computer, then encoded as a WAV file using a C++ program. The iPod plays the WAV file with the data through a single-stage opamp amplifier connected to the headphone jack. The amplifier is used to drive the electromagnet. Video embedded after the jump.
By no means is this a new idea. There have been a lot of magnetic stripe projects and software. This project in particular references the 1992 Phrack article “A Day in the Life of a Flux reversal” by [Count Zero].