The 2014 Sensors Expo and Conference held in late June provided a high level of diversity in both the technical presentations and on the exhibition floor. The Internet of Things, M2M and wireless, energy harvesting, MEMS, and high-performance computing and communications (HPCC) each had locations on the exhibition floor. Outside of these specialized areas, software, semiconductors, batteries, PCBs, and sensors occupied the booths.
Two conference days kicked off with a networking breakfast followed by a keynote address. The first day’s speaker was Luigi Gentile Polese from the National Renewable Energy Laboratory, who discussed managing the energy used by buildings—of the approximately 98 quadrillion BTU annually used in the United States, about 40% goes to buildings.
Gentile Polese described image processing occupancy sensor (IPOS) technology that goes well beyond the capabilities of infrared or motion detectors. In addition to occupancy, facial recognition adds security, and motion is indicative of a person’s activities, which could affect the amount of light or heat needed.
IPOS is related to sensor fusion and virtual sensing. Sensor fusion combines inputs from several sensors to produce a result that is better than if each sensor were considered separately. As an example of virtual sensing, the amount of CO2 in a building was estimated by monitoring Wi-Fi activity. By identifying the number of human users and assuming that they formed some proportion of the total number of occupants, a CO2 concentration could be estimated
Dr. Logan Liu, University of Illinois at Urbana-Champaign, kicked off the second morning’s agenda. His presentation focused on MoboSens technology that Dr. Liu’s group developed. Each sensor attaches to a smart phone and detects chemicals at the molecular level. With the right sensors, a user can measure water contaminates as well as biomolecules in body fluids. Data is generated by a mobile computing app in the smart phone and transmitted to the cloud for further analysis.
Conference Sessions
During the two days, 54 topics in six tracks were presented. Here are the highlights from several sessions I attended.
A Wearable Sensor System: Reality or Dream? stressed low battery power drain but also distinguished between medical applications and health/wellness applications based on power, data quality, and authentication. For medical tests, authentication and data quality were most important. In contrast, health/wellness system selling points begin with low power drain. Because of the commercial nature of the health/wellness website marketing efforts, authentication should include company claims as well as user ID.
Advantages of Sensor Conditioning Using SENT Interface took attendees by surprise: No one knew what the automotive protocol did. SENT stands for single edge nibble transmission in which groups of four bits (a nibble) are output. A ZDMI chip used as an example converts analog sensor signals to 12-bit data with about a 1-kHz output rate. The data is output with a CRC check and at a full 5-V level to improve noise immunity.
Freescale Semiconductor discussed sensor trends in an HPCC area theater session. For the medical and automotive markets, Freescale offers at least 15-year sensor availability. In addition to making many individual sensors, Freescale provides the controllers, sensors, and wireless charging components used in the wearable reference platform (WaRP) initiative.
3D LIDAR Imaging in the Presence of Obscurants in Harsh Environments described a solution to helicopters crashing when trying to land in dusty places like Afghanistan and Iraq. LIDAR (light detection and ranging) illuminates a target and detects the reflected signal, much as RADAR does, but with laser light rather than radio waves. Advanced spatial and time-domain filtering provided a 3-D LIDAR cockpit system with clear views of the landing site in spite of the obscuring dust.
Innovative Sensor Technologies for Emerging Automotive Applications dealt with sensor trends. Many mandated automotive sensor applications are safety-related, but emission control also is a large area. Of the expected 5% to 10% CAGR in sensors and microprocessors through 2017, some will come from hydrogen fuel pressure sensors and lane-change-assist sensors, but most will be from the Asian/Chinese market growth.
Smart Fabrics Changing How We Feel the World: Insight into Medical Application described uses for a three-layer large-area pressure sensor. It has orthogonal top and bottom grids made of a stretchable fabric with alternating conducting and insulating stripes with a thin resistive rubber layer between the fabric layers. When pressure is applied to the fabric/rubber sandwich, the pressure location and degree can be found by scanning the X-Y conductors.
One application for this sensor addresses bed sores that affect at least one million patients per year in the United States, of which 30,000 die. A smart bed with numerous air-filled support cells and a top layer of the smart fabric automatically can adjust the air pressure to redistribute the patient’s weight when high pressure is sensed in a location.
Conclusion
Sensors are everywhere today, and tomorrow promises even greater proliferation. It’s an exciting prospect.