Browsing by Author "Chang, Wen-Ying"

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An electrochemical dopamine sensor with a CMOS detection circuit
(2008-07-01)
Chan, Feng-Lin
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Chang, Wen-Ying
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Kuo, Li-Min
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Lin, Chih-Heng
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Wang, Shi-Wei
This paper presents the integration of interdigitated microelectrodes and a CMOS circuit for electrochemical sensing of the neurotransmitter dopamine. Gold electrodes with a gap of 3 mu m are fabricated by the lift-off technique. The CMOS sensing circuit has a current gain of 10, an integrating capacitor of 4 pF, and a measured dynamic range of 60 dB. The applied reduction and oxidation potentials are determined by voltammetry at about -0.2 V and 0.6 V, respectively. The measured collection efficiency can reach up to 84%. The produced oxidation current with respect to dopamine concentration averages 0.44 nA mu M(-1).
An electrochemical dopamine sensor with CMOS detection circuit
(2007-01-01)
Zhan, Feng-Lin
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Kuo, Li-Min
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Wang, Shi-Wei
;
Lu, Michael S. -C.
;
Chang, Wen-Ying
This paper presents the use of interdigitated microelectrodes as the platform for electrochemical sensing of the neurotransmitter dopamine. Gold electrodes with gaps ranging between 3 gm to 7 gm are fabricated by the lift-off technique. The reduction and oxidation potentials for dopamine are determined by voltammetry using the fabricated microelectrodes. A CMOS sensing circuit is used to amplify the electrochemical current produced by the working electrodes. Experimental result shows that for a dopamine concentration of 10 mu M the measured current value is 11 pA.
Design of a Novel Flexible Capacitive Sensing Mattress for Monitoring Sleeping Respiratory
(2014-11-01)
Chang, Wen-Ying
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Huang, Chien-Chun
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Chen, Chi-Chun
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Chang, Chih-Cheng
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Yang, Chin-Lung
In this paper, an algorithm to extract respiration signals using a flexible projected capacitive sensing mattress (FPCSM) designed for personal health assessment is proposed. Unlike the interfaces of conventional measurement systems for poly-somnography (PSG) and other alternative contemporary systems, the proposed FPCSM uses projected capacitive sensing capability that is not worn or attached to the body. The FPCSM is composed of a multi-electrode sensor array that can not only observe gestures and motion behaviors, but also enables the FPCSM to function as a respiration monitor during sleep using the proposed approach. To improve long-term monitoring when body movement is possible, the FPCSM enables the selection of data from the sensing array, and the FPCSM methodology selects the electrodes with the optimal signals after the application of a channel reduction algorithm that counts the reversals in the capacitive sensing signals as a quality indicator. The simple algorithm is implemented in the time domain. The FPCSM system is used in experimental tests and is simultaneously compared with a commercial PSG system for verification. Multiple synchronous measurements are performed from different locations of body contact, and parallel data sets are collected. The experimental comparison yields a correlation coefficient of 0.88 between FPCSM and PSG, demonstrating the feasibility of the system design.