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Embedded Impedance Analyzer Based On System-On-Chip
Marco Gierlinger
Supervision: Univ.-Prof. Dipl.-Ing. Dr. Bernhard Zagar
An embedded device is built to measure unknown impedances within a wide measurement range. This thesis tries to find a practical solution based on a single-chip integrated circuit by Analog Devices called AD5933. The device is supposed to be
built as easy as possible and should take full advantage of the chip.
An analog-front-end is discussed and implemented in the hardware design, which is recommended by Analog Devices in addition to the AD5933. Further, it is extended with relays to switch through multiple reference resistors to calibrate the system.
Figure 1: Embedded Impedance Analyzer, front side.
Measurement results are shown via Bode plots on a display. The control of the hardware is done by a Raspberry Pi 3. Accordingly, a software is written, too. The evaluation board of the AD5933 is used to compare measurement results and to
analyze the disadvantages and advantages of the custom designed PCB.
Keywords: self capacitance, capacitive proximity sensors, human finger interaction, touchless gesture recognition, capacitive positioning
March 3rd, 2019
