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Prototyping a Capacitive Sensing Device for Gesture Recognition Chenglong Lin

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Prototyping a Capacitive Sensing Device for Gesture Recognition Chenglong Lin University of Arkansas, Fayetteville ScholarWorks@UARK Computer Science and Computer Engineering Computer Science and Computer Engineering Undergraduate Honors Theses 5-2019 Prototyping a Capacitive Sensing Device for Gesture Recognition Chenglong Lin Follow this and additional works at: https://scholarworks.uark.edu/csceuht Part of the Digital Circuits Commons, Electrical and Electronics Commons, Electronic Devices and Semiconductor Manufacturing Commons, and the Service Learning Commons Recommended Citation Lin, Chenglong, "Prototyping a Capacitive Sensing Device for Gesture Recognition" (2019). Computer Science and Computer Engineering Undergraduate Honors Theses. 70. https://scholarworks.uark.edu/csceuht/70 This Thesis is brought to you for free and open access by the Computer Science and Computer Engineering at ScholarWorks@UARK. It has been accepted for inclusion in Computer Science and Computer Engineering Undergraduate Honors Theses by an authorized administrator of ScholarWorks@UARK. For more information, please contact [email protected]. Prototyping a Capacitive Sensing Device for Gesture Recognition Presented to the Department of Computer Science and Computer Engineering College of Engineering University of Arkansas Fayetteville, AR In Partial Fulfillment of the Requirements for the award of Honors for Bachelor of Science in Computer Engineering by Chenglong Lin May 2019 Abstract Capacitive sensing is a technology that can detect proximity and touch. It can also be utilized to measure position and acceleration of gesture motions. This technology has many applications, such as replacing mechanical buttons in a gaming device interface, detecting respiration rate without direct contact with the skin, and providing gesture sensing capability for rehabilitation devices. In this thesis, an approach to prototype a capacitive gesture sensing device using the Eagle PCB design software is demonstrated. In addition, this paper tested and evaluated the resulting prototype device, validating the effectiveness of the approach. Acknowledgments I would like to express my sincere gratitude to Dr. Pat Parkerson and Dr. Alexander Nelson for their mentorship in this research project. Their encouragement and expertise helped me grow as a researcher and writer. I would also like to thank Dr. David Andrews for serving in my honors thesis defense committee and providing feedback and recommendations regarding my thesis. Furthermore, I would also like to give an immense thank you to my lab partners Mr. Haoyan Liu and Mr. Enrique Headley for providing help and support throughout this research. Their peer review and feedback greatly helped the thesis writing. Finally, I would like to thank my family for their love, help, and support throughout my undergraduate career. i Table of Contents List of Tables ..................................................................................................................... iv List of Figures ......................................................................................................................v Chapter 1: Introduction ........................................................................................................1 1.1 Problem ....................................................................................................................1 1.2 Thesis statement .......................................................................................................2 1.3 Approach ..................................................................................................................2 Chapter 2: Background ........................................................................................................2 2.1 MSP430FR2633 MCU.............................................................................................2 2.2 Capacitance ..............................................................................................................3 2.3 Capacitive sensing ...................................................................................................4 2.3.1 Self-capacitance detection ............................................................................. 4 2.3.2 Mutual-capacitance detection ........................................................................ 5 2.3.3 Charge Transfer Method ................................................................................ 7 Chapter 3: Design and Implementation ...............................................................................7 3.1 Schematic design .....................................................................................................7 3.1.1 MSP430FR2633 MCU and ESD (Electrostatic discharge) protection .......... 7 3.1.2 Clock module ................................................................................................. 8 3.1.3 Data communication ...................................................................................... 8 3.1.4 Programming.................................................................................................. 9 3.1.5 Reset ............................................................................................................. 10 3.1.6 Power and LED indicator............................................................................. 10 ii 3.2 Eagle — Library and Device .................................................................................11 3.2.1 Library and Device ...................................................................................... 11 3.2.2 Footprint ....................................................................................................... 11 3.2.3 Symbol ......................................................................................................... 12 3.3 Eagle — Schematic ................................................................................................12 3.3.1 Nets and Net tagging .................................................................................... 12 3.3.2 ERC (Electrical rule check) ......................................................................... 13 3.4 Eagle — Placement and Route ..............................................................................13 3.4.1 Routing — trace and via .............................................................................. 13 3.4.2 Hatched ground ............................................................................................ 13 3.4.3 Silkscreen ..................................................................................................... 14 3.4.4 Ratsnest ........................................................................................................ 14 3.4.5 Crystal oscillator placement ......................................................................... 14 3.4.6 Captivate VREG (LDO voltage regulator) decoupling capacitor placement .................................................................................................. 14 3.4.7 DRC (Design rule check) ............................................................................. 14 3.5 Manufacture and Soldering ....................................................................................15 3.5.1 Pre-tin pads .................................................................................................. 15 3.5.2 Solder paste .................................................................................................. 15 3.6 Programming..........................................................................................................15 3.6.1 Captivate design center ................................................................................ 15 3.6.2 Code composer studio and MSP-FET programmer ..................................... 16 iii Chapter 4: Test and Evaluation ..........................................................................................16 4.1 Board specification ................................................................................................16 4.2 Self-capacitance and Mutual-capacitance mode test .............................................17 4.3 Power consumption ................................................................................................18 Chapter 5: Conclusion and Future work ............................................................................20 5.1 Conclusion .............................................................................................................20 5.2 Future work ............................................................................................................20 References ..........................................................................................................................22 Appendix ............................................................................................................................24 iv List of Tables Table 1: Self-capacitance sensor count experiment .......................................................... 24 Table 2: Mutual-capacitance sensor count experiment ..................................................... 24 Table 3: LPM0 power measurement ................................................................................. 24 Table 4: LPM3 power measurement ................................................................................. 25 Table 5: LPM4 power measurement ................................................................................. 25 v List of Figures Figure 1: MSP430 development
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