Chris Harrison, a PhD candidate in the Human-Computer Interaction Institute at Carnegie Mellon University, has created Acoustic Barcodes, an inexpensive and effective way to attach a binary ID to almost any surface. Using a simple contact mic, the system reads the audible waveform given off when an object — like a fingernail, card, or phone — runs across the notches that make up the unique barcodes. As demonstrated in the video below, Acoustic Barcodes can be built into store window displays to provide product information or can be used to initiate file syncing with your smartphone by dragging the device across a coded surface. Acoustic Barcodes can be applied to a number of materials, ranging from wood and metal to glass and stone, although we prefer to not slide our phones against any rigid surface if at all possible. While the barcodes may not be completely useful for most people, it can potentially be used alongside other tactile technologies like Braille to assist those who are vision impaired.