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Think Outside the Chip: MEMS-Based Systems Solutions

In the United States alone, there are 583,000 bridges. The American Society of Civil Engineers (ASCE) reports that approximately 25% of these are structurally deficient or functionally obsolete. ASCE also reports that of the 76,926 dams that exist in the US, 1,819 have high hazard potential and are now considered deficient with the public at risk. Many of the over 2 million lines of natural gas pipelines in the US are considered antiquated and prone to failure. Finally, many of the over 100,000 miles of levees are reported to have structural integrity problems.

This broad and aging infrastructure is a prime candidate for wireless sensor networks. The University of Michigan WIMSS Center team has instrumented approximately ten bridges worldwide using this WASN approach. In keeping with the WIMS “mantra” of integration, they have adopted an approach using 3D chip stacking as a means to a robust and space-conscious package to their solution (Figure 2). Researchers believe that this real-time monitoring approach can be an early indicator of structural failure, resulting in the possible saving of lives in addition to reducing maintenance and inspection costs.

Future Application Opportunities

MBSS principles can be applied most effectively to many applications. Our research points to “smart building” systems and home-based point-of-care patient monitoring as holding promise for future large-volume applications of MBSS. In the area of smart buildings, the same principles discussed in the infrastructure monitoring above can be applied to make buildings more energy efficient, safer, and the environment more pleasant and healthy to its occupants. All of the constituents defined in Figure 1 apply here: sensors including temperature, airflow rate, humidity, air quality/gas constituents, light levels, motion sensors, and others are readily available as off-the-shelf commodities. Wireless network chips are also off-the-shelf commodities. Also readily available are ASICs and high-performance power sources (i.e. batteries). The challenge from an engineering perspective is to create the systems-based solution, the applications algorithms, and the integration of all of these functionalities into a small and robust package made for easy deployment in buildings at a price that provides users with quick paybacks.

Conclusions

Although MBSS has existed for many years, the proliferation of this approach is being driven from the tech nology push perspective with the availability of low-cost MEMS devices, signal conditioning ASICs, and DSP, as well as lowcost packaging such as wafer scale packaging and high-throughput testing. Fortunately, there is an “applications/ market” pull situation that co-exists, making this a very interesting situation for widespread adoption in numerous high-growth applications.

The need for gesture recognition in games, toys, computer peripherals (mice), medical, sports, and fitness bodes well for this approach. Add - itionally, as the need to better understand the quality of food and water, as well as the chemical and biological composition of many substances to enhance society’s quality of life, the MBSS approach for spectrometers and chromatographs for easy-to-use and low-cost handheld instruments will create many application successes.

However, the ultimate forcing factor to the adoption of MBSS by developers will be the continuing need for welldefined and defensible product differentiation and higher profit margins vis-à-vis higher levels of integration and value-added that optimally satisfy the customer’s applications needs.

This article was written by Roger H. Grace, President, Roger Grace Associates, Naples, FL. For more information, visit http://info.hotims.com/40435-122.