News and New Products

Fingers good for more than just QWERTY

By Bill Schweber -- EDN, 11/13/2003

Things are truly going digital everywhere—not just in the numerical, but also in the literal sense—as two recently introduced products vividly demonstrate. The MicroNav from Interlink Electronics may meet your requirements if you need the equivalent of full mouselike action and 360° navigation on a cell phone, PDA, GPS unit, or similar tiny product (Picture). This component uses a four-quadrant force-sensing-resistor technique to assess where you are pressing and moving your finger. An A/D converter converts the signal outputs, and firmware interprets the results.

The company offers the 10×10-mm, 1.4-mm-high device as a stand-alone sensor with firmware in object-code libraries; as a chip-plus-sensor device, including a serial, USB, or PS/2 interfaces; or as a drop-in sensor on a pc board with a microprocessor and a rubber actuator top. The basic sensor, which you can handle like any other component in the assembly cycle, sells for less than $1 (OEM quantities).

For applications requiring biometric-type security and access to electronic devices from cell phones, PDAs, or cars, AuthenTec has condensed its full-press fingerprint sensor pad into a linear “slide” sensor, in which you pull your finger across the sensing surface. This lower cost, smaller sensor combines with software to recognize and validate the sensed signals. To avoid spoofing, the AES2500 EntréPad uses RF techniques rather than sense the “living layer” of skin below the ridge and valley pattern, rather than measuring surface factors. You pull your finger across the 192×16-pixel detection matrix with its 9.75×0.81-mm surface area to expose and register your fingerprint. The associated software stores only key parameters of the image, rather than the image itself, so that no one can use your fingerprint data to replicate your image.

Interlink Electronics Inc, www.interlinkelectronics.com.

AuthenTec Inc, www.authentec.com.