Solar powered sensor is only 9 mm3 in volume

Citation

(2010), "Solar powered sensor is only 9 mm3 in volume", Sensor Review, Vol. 30 No. 3. https://doi.org/10.1108/sr.2010.08730cad.001

Solar powered sensor is only 9 mm3 in volume

Solar powered sensor is only 9 mm³ in volume

Article Type: New products From: Sensor Review, Volume 30, Issue 3

Engineers at the University of Michigan in Ann Arbor have developed a solar powered sensor that is up to 1,000 times smaller than similar currently available commercially sensors. In a package, which is only 2.5×3.5×1 mm, the engineers have packed a 32-bit processor chip, solar cell and battery (Figure 1).

Figure 1 Photo of University of Michigan developed energy harvesting sensor on coin for size comparison

The device employs the ARM processor, an industry popular 32-bit device. It is noted for its low power, energy efficient features such as deep sleep mode, wake up interrupt controller and low-leakage mode. The sensor can go from deep sleep to fully active mode almost instantaneously. The sensor is expected to run almost perpetually when exposed to just reasonable light levels. The limiting factor is the battery, which is expected to have a life of a many years.

University developers say the key innovation is the method used to manage power. The processor needs only about 0.5 V to function and the low-voltage, thin film Cymbet battery puts out close to 4 V. The voltage, which is essentially the operating pressure of electric current, must be reduced to make the system function most efficiently. The traditional method of reducing voltage uses much more energy than the processor would. One of the techniques employed is to slow the power management clock when the units power needs are low. “We skip beats” if it is determined the voltage is adequate, said Professor Dennis Sylvester, Associate Professor in Electrical and Computer Engineering.

The university team is working with doctors on potential medical applications. The approach might offer less-invasive means to monitor pressure changes in the eyes, brain, and in tumors in patients with glaucoma, head trauma, or cancer. In the body, the sensor could conceivable harvest energy from movement or heat, rather than light.

The research is funded by the National Science Foundation, the Defense Advanced Research Projects Agency, the National Institute of Standards and Technology, the Focus Center Research Programs and ARM. For more info on the solar powered sensor visit: http://vlsida.eecs.umich.edu