As the interface between electronics and the real world, sensors frequently play an enabling role in the proliferation of devices such as smartphones to and ever expanding array of applications. Our research group leverages the expertise and facilities of the Swarm Laboratory and the Berkeley Sensor & Actuator Center to design and fabricate sensors with new capabilities or improved performance and explore novel usage scenarios./
The proliferation of ever more powerful electronic devices such as smart phones with ready access to proprietary data creates a pressing need for a reliable and user friendly biometric identifications with both improved accuracy and ease of use compared to passwords.
Fingerprints have been used for centuries for unambiguous identification. Although electronic sensors have been available for some time, current optical and capactivie solutions have found only limited adoptions owing to their poor handling of common real world imperfections such as stains, moisture, or oils and being easily foiled by proxies.
This project leverages our expertise with ultrasonic trasducers to fabricate a fingerprint sensors with significantly improved accuracy and robustness. Unlike optical and capacitive solutions, the ultrasonic sensor measures the dermal image behind the screen and is therefore not susceptible to superficial dirt and scars.
Already widely used for camera image stabilization, smart phone user interfaces, and in automotive crash avoidance and detection, GPS assisted and indoor navigation is the next "killer app" for this versatile device. Unfortunately the high drift of present gyroscopes severely limits their usefulness for this important task.
This research applies precision electronic circuit techniques such as chopper stabilization and direct rate-to-digital conversion to MEMS gyroscopes with the goal of achieving sub degree/hour accuracy.
Ref: M. H. Kline et al, MEMS Gyroscope Bias Drift Cancellation using Continuous-Time Mode Reversal, Transducers 2013.
Flow cytometers are very powerful medical diagnostic instruments used to diagnose and monitor a wide variety of immunological diseases such as HIV and are also a highly versatile and accurate instrument used in ensuring food safety and evaluating waterborne diseases. Unfortunately they are also very expensive and can be used only by trained staff. This project solves both problems with an entire flow cytometer that fits on an electronic chip. This not only reduces the cost and size, but also allows the device to be used by anyone, anywhere.
Accepted for publication at ISSCC 2014
This project uses custom piezo-electric transducer arrays for ultrasonic imaging. The ultra-thin membrane design results in good coupling in air, enabling a wide range of applications including 3D localization, touch screens, gesture recognition, ranging with millimeter accuracy, air speed measurements and gas flow sensors. Compared to optical methods, ultrasound based solution have orders-of-magnitude lower power dissipation, making this technology ideal for application in battery powered devices such as smart phones.
Named at ISSCC 2014 by EE Times as one of 5 technologies to watch.
The research results from this projects have been transferred to Chirp Microsystems for commercialization under license from UC Berkeley.