Portable Parameter Analyser for Organs-on-Chip

Calibration and GUI

Bachelor thesis (2020)

Authors

J.J. Noordhoek Electrical Engineering, Mathematics and Computer Science
Y.U. Wesseling Electrical Engineering, Mathematics and Computer Science

Contributors

Massimo Mastrangeli Electronic Components, Technology and Materials - EEMCS (supervisor 1)
M. Spirito Electronics - EEMCS (supervisor 1)
Faculty
Electrical Engineering, Mathematics and Computer Science
Copyright: © 2020 Jillis Noordhoek, Yme Wesseling
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Published Date

30-06-2020

Language

English

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Faculty

Electrical Engineering, Mathematics and Computer Science

Abstract

Until now parameter analysers for Organ-on-Chips (OoCs) have needed bulky multi-probe setups that do not fit in biological research labs. For this reason a bachelor graduation project was proposed to get one of the sensors designed by the Electronic Components, Technology and Materials group (ECTM) out of the lab and into the hands of potential end users. This thesis is one of three from that project, and describes the calibration and user interface components of the portable parameter analyzer that is developed for the OoC sensor.

First, an analysis is performed on the amplifier design that was given with the sensor. The analysis showed that the biggest sources of error in the overall gain are the offset and gain error, while non-linearity was not significant. Therefore, a two-point calibration method was deemed sufficient for the amplifier calibration. It is performed by taking two reference voltages as input of the amplifier, and measuring the corresponding output. With those points the actual gain and offset voltage can be calculated and corrected in measurements.

Because of circumstances it was not possible to test in a lab environment whether the amplifier and the two-point method would meet the requirements. Therefore a second calibration method is proposed, the `sweep' method. For each input voltage step the corresponding output voltage is measured. This mapping can be stored in memory, and any future measurement can be looked up to find the correct voltage. The sweep method can also be used with a slight modification of the current hardware in order to simply plot the gain of the amplifier, to verify that it is linear as intended.

Because the portable parameter analyzer is operated remotely, there was a need to develop a communication protocol on top of the Bluetooth link, in order to allow for parallel development of the GUI and embedded software on the analyzer. Once the communication between GUI and analyzer was defined, it was also possible for the other group to calculate the power consumption of the communication module.

Finally, a Graphical User Interface (GUI) needs to be developed that can interact with the analyzer (connect, change settings, retrieve data, etc.) and it should display and store the measured data. A framework called Qt is chosen for developing the GUI, and a graphical design was made. Two modules are implemented in the GUI: A Bluetooth scanner to connect to the analyzer, and a way to plot data from the analyzer.