Smart Dust: Swarms of Mini Sensor Nodes Powered By Integrated Solar Cells

Tiny solar cells applied directly to a silicon chip are a potential way of efficiently and reliably powering wireless sensor networks in the near future. Above all, this would simplify large-scale applications, for instance in agriculture.

The solar cell sits directly on the sensor module’s silicon chip.Such sensor networks made up of countless individual sensor modules that communicate wirelessly with one another have the capacity to measure local parameters over large areas, and to then pass on these data over multiple sensor modules to a central station. This makes sensor networks suitable for a wide range of applications, whether for fire prevention or monitoring large areas of farmland.

The issue of how to power the individual sensor modules remains a sticking point in these sorts of applications. Wiring the sensors together is hardly a viable option nowadays due to the cumbersome and costly installation. What’s more, many applications require the sensor network to blend unobtrusively into the surroundings and not to have an impact on the aesthetics.

An example of this would be the systems used for adjusting window positions as part of smart building management programs. Using batteries to power the sensor network does eliminate the need for inconvenient cables, but the amount of maintenance involved in replacing the batteries regularly as required should not be underestimated, particularly in large networks.

Now, researchers from the Fraunhofer Institute for Microelectronic Circuits and Systems IMS have developed an ingenious alternative based on SOLCHIP Ltd IP. The resource they have harnessed to provide power is one that is freely available in almost any location: sunlight. “We use special process steps to place a mini solar cell straight on sensor modules’ silicon chips,” explains Dr. Andreas Goehlich, who heads up the project for Fraunhofer IMS.


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