Make a Metal Fingerprint

iButton Reader MAXIM Integrated Products

What the heck is an iButton, you ask? Manufactured by MAXIM Integrated Products, Dallas Semiconductor, an iButton is a fingernail-sized computer chip housed inside a stainless steel can. This can acts as a unique conductive connection that enables the enclosed computer chip to form a speedy 1-wire interface with a PC, PDA, or embedded computer. Throw some software into the mix and you have a handy data ID without the messy airborne detection problems that are commonly associated with RFID.

Just press an iButton against any 1-wire interface and bingo—you’re logged in. This connection protocol can be used for developing some nifty access management products: software authorization keys, access fobs, and timekeeping loggers. Anywhere RFID can be used, iButton can be used without the fear of spurious radio detection. It’s like a metal fingerprint.

MAXIM has also created some very specialized iButtons that can be used for logging temperature, humidity, password-challenge-responses, and real time clock ticks. Furthermore, there are iButtons that can be programmed and reprogrammed with unique personal information. Kinda like a micro-sized dog tag.

iButton Reader Dimensions:  MAXIM Integrated Products

If you’d like to get started experimenting with iButtons, BG Micro can supply you with a whole fist full of metal fingerprints for under $5—approximately $1.65 per hand. Then head over to Digi-Key for the Dallas Semiconductor USB-to-iButton Adapter, DS9490B. This $37 adapter can hold one iButton for direct insertion into any USB port. Your final stop is at the iButton Mothership—the MAXIM Web site. Here you can find a 1-wire software authorization SDK (for experimenting with developing a PC-based fingerprint ID system: aka security dongle), 1-wire drivers, and a 1-wire API for Java. Plus there are lots of application notes for stimulating your creative iButton juices.

In no time, you could be saying hasta la vista, baby to your flesh-based carbon-form fingerprints.