Low-Cost Interfaces for Sensors and Sensor Systems
This paper discusses the basic ideas, circuitry and applications of a novel family of low-cost transducer interfaces. These interfaces, which are directly read-out by a microcontroller, service the following sensor elements: Pt resistors, thermistors, potentiometers resistors, capacitors, resistive bridges and voltage- and current sources. It is shown that, even when using lowcost CMOS technology, these interface and sensor systems can have a rather high accuracy. The interfaces have been designed for applications where the sensors signals have a low to moderate bandwidth. The main test results for some typical applications are reported in this paper. The accuracy amounts to 1 to 15 bits for a measurement time of 1 ms to 100ms. The number of external components has been kept to a minimum.
KeywordsMeasurement Phase Parasitic Capacitance Relaxation Oscillator Sensor Element Synchronous Detection
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- 1.F.M.L. van der Goes, “Low-cost smart sensor interfacing”, Ph.D. thesis, Delft University of Technology, The Netherlands, April 1996.Google Scholar
- 2.F.M.L. van der Goes and G.C.M. Meijer, “Sigma-Delta versus oscillator-based A/D convertors in low-cost accurate sensor systems”, Proc. Instrumentation and Measurement Imtc/96, 1996.Google Scholar
- 3.G.C.M. Meijer, J. van Drecht, P.C. de Jong and H. Neuteboom, “New concepts for smart signal processors and their application to PSD displacement transducers”, Sensors and Actuators A35, pp. 23–30, 1992.Google Scholar
- 5.G.C.M. Meijer, “Concepts and focus points for intelligent sensor systems”, Sensors and Acutators A, 41–42, pp. 183–191, 1992.Google Scholar
- 6.F.M.L. van der Goes and G.C.M. Meijer, “A simple and accurate dynamic voltage divider for resistive bridge transducers”, Proc. Instrumentation and Measurement Conference, Imtc/94, Japan, pp. 784–787, 1994.Google Scholar
- 7.P.C. de Jong, Ned. Octrooiaanvrage nr. 1002732. “Instrumentatieversterker”, 1996.Google Scholar
- 9.G. C. M. Meijer, Patent Appl. 1000222, April 1995.Google Scholar
- 10.S.H. Khadouri, F.M.L. van der Goes and G.C.M. Meijer, “A smart CMOS interface system for thermocouples”, Proc. Instrumentation and Measurement Conference, Imtc/96, Brussels, 1996.Google Scholar