Page 123 - MEMS Mechanical Sensors

112 Mechanical Transduction Techniques

can communicate with each other in addition to the host system. There are many
examples of commercial protocols that are used in smart sensor systems, but we
will not go into detail here. It is sufficient to be aware that the smart sensor will
often have to deal with situations such as requests for data, calibration signals,
error checking, and message identification. Of course, it is feasible in some applica-
tions that the data communications may simply be a unit that provides an analog
voltage or current signal.
The control processor often takes the form of a microprocessor. It is generally
the central component within the smart sensor and is connected to most of the other
elements, as we have already seen. The software routines are implemented within
the processor and these will be stored within the memory unit. The control processor
may also issue requests for self-test routines or set the gain of the amplifier.

References

[1] Middelhoek, S., and S. A. Audet, Silicon Sensors, New York: Academic Press, 1989.
[2] http://www.qprox.com.
[3] Tudor, M. J., and S. P. Beeby, “Resonant Sensors: Fundamentals and State of the Art,” Sen-
sors and Materials, Vol. 9, No. 3, 1997, pp. 1–15.
[4] Langdon, R. M., “Resonator Sensors—A Review,” J. Phys. E: Sci. Instrum., Vol. 18, 1985,
pp. 103–115.
[5] Greenwood, J. C., “Silicon in Mechanical Sensors,” J. Phys. E: Sci. Instrum., Vol. 21, 1988,
pp. 1114–1128.
[6] Stemme, G., “ Resonant Silicon Sensors,” J. Micromech. Microeng., Vol. 1, 1991, pp.
113–125.
[7] Eernisse E. P., R. W. Ward, and R. B. Wiggins, “Survey of Quartz Bulk Resonator Sensor
Technologies,” IEEE Trans. Ultrasonics Ferroelectrics and Frequency Control, Vol. 35,
No. 3, May 1988, pp. 323–330.
[8] Prak, A., T. S. J. Lammerink, and J. H. J. Fluitman, “Review of Excitation and Detection
Mechanisms for Micromechanical Resonators,” Sensors and Materials, Vol. 5, No. 3, 1993,
pp. 143–181.
[9] Newell, W. E., “Miniaturization of Tuning Forks,” Science, Vol. 161, September 1968, pp.
1320–1326.
[10] Beeby, S. P., and M. J. Tudor, “Modeling and Optimization of Micromachined Silicon
Resonators,” J. Micromech. Microeng., Vol. 5, 1995, pp. 103–105.
[11] Andres, M. V., K. H. W. Foulds, and M. J. Tudor, “Nonlinear Vibrations and Hysteresis of
Micromachined Silicon Resonators Designed as Frequency Out Sensors,” ElectronicsLet-
ters, Vol. 23, No. 18, August 27, 1987, pp. 952–954.
[12] Akiyama, T., and S. Katsufusa, “A New Step Motion of Polysilicon Microstructures,” Proc
MEMS ’93, 1993, pp. 272–277.
[13] Walker, J. A., K. J. Gabriel, and M. Mehregany, “Thin-Film Processing of TiNi Shape Mem-
ory Alloy,” Sensors and Actuators, Vol. A21–23, 1990, pp. 243–246.
[14] Judy, J. W., R. S. Muller, and H. H. Zappe, “Magnetic Microactuation of Polysilicon Flex-
ure Structures,” Tech. Dig. Solid State Sensor and Actuator Workshop, Hilton Head, SC,
1994, pp. 43–48.
[15] Brignell, J. E., and N. M. White, Intelligent Sensor Systems, Bristol, England: IOP Publish-
ing, 1994.
[16] Gardner, J. W., V. K. Varadan, and O. O. Awadelkarim, Microsensors, MEMS and Smart
Devices, Chichester: John Wiley and Sons, 2001.
[17] Frank, R., Understanding Smart Sensors, 2nd ed., Norwood, MA: Artech House, 2000.