3D Electric-Field Imager Yields New Sensing Apps

Motorola's MC33794, an electric-field imaging IC, combines with an external microcontroller and simple electrodes to implement occupant sensing systems. Such systems help to deploy automobile airbags intelligently. Yet with its high level of functional integration, the chip may enable a new class of low-level 3D electric-field imaging applications. The chip replaces more than 70 components in existing designs.

The MC33794 generates a high-purity sinewave, steers it to one of nine external electrodes, and measures the resultant field coupled onto the nondriven electrodes. The resulting data is fed to an external microcontroller, which can be programmed to interpret that data and determine the characteristics of the object interfering in that field (see the figure).

Motorola's Analog Products Division developed the electric-field imaging IC in collaboration with Motorola's DigitalDNA Laboratory at the Massachusetts Institute of Technology's Media Lab and with Elesys North America. Housed in a 44-lead HSOP, the IC costs $3.09 each per 10,000. For more details, go to www.motorola.com/semiconductors.