Development of an Electronic Nose-Tongue Data Acquisition System using a Microcontroller

An ad-hoc data acquisition system was constructed in order to control an array of different types of sensors and to collect their data. The system will be used as the core for electronic nose and tongue systems used for classifying and distinguishing different levels of contamination in water and other types of liquid. The system consists of analog and digital electronics as well as software for a microcontroller and a PC. The heart of the system is a PIC microcontroller that can communicate with the real world and with a PC. With the real world it is referred to analogue devices that measure things that are infinitely variable, they are not quantized like in the digital world which is an approximation of the real world. A microcontroller is a small computer fit into a single chip. This computer is a microprocessor together with memory and I/O ports. Microchip is a company that has produced popular microcontrollers called PIC’s. The microprocessor was programmed in the language C. The system can take samples at accurate time intervals. A LabVIEW program was developed so that the system can be controlled with a user friendly interface. The sensors can be monitored in the LabVIEW program and the data can be exported to a spread sheet text document, ready to be opened in another program for analysis. With serial transmission the designed data acquisition board cannot only be interfaced with LabVIEW on a PC running Windows, but also with Linux or Windows Mobile. The system is robust, economic and portable. The report tries to describe how the development was done

Development of a Portable Water Quality Analyzer

A portable water analyzer based on a voltammetric electronic tongue has been developed. The system uses an electrochemical cell with two working electrodes as sensors, a computer controlled potentiostat, and software based on multivariate data analysis for pattern recognition. The system is suitable to differentiate laboratory made and real in-situ river water samples contaminated with different amounts of Escherichia coli. This bacteria is not only one of the main indicators for water quality, but also a main concern for public health, affecting especially people living in high-burden, resource-limiting settings

How the Nature of Triphenylamine-Polyene Dyes in Dye-Sensitized Solar Cells Affects the Open-Circuit Voltage and Electron Lifetimes

Three donor-linker-acceptor triphenylamine-based cyanoacrylic acid org. dyes used for dye-sensitized solar cells (DSCs) were examd. with respect to their effect on the open-circuit voltage (Voc). The previous study showed a decrease in Voc for DSCs based on dyes with increased mol. size (increased linker conjugation). The authors study the origin of Voc with respect to (a) conduction band (ECB) positions of TiO2 and (b) degree of recombination between electrons in TiO2 and electrolyte acceptor species at the interface. These parameters were studied as a function of dye structure, dye load, and I2 concn. Two types of behavior were identified: the smaller polyene dyes show a surface-protecting effect preventing recombination upon increased dye loading, whereas the larger dyes enhance the recombination. How the different dye structures affect the recombination is discussed in terms of dye surface blocking and intermol. interactions between dyes and electrolyte acceptor species

Electrochemical aspects of display technology based on nanostructured titanium dioxide with attached viologen chromophores

Progress in recent years in the field of electrochromic displays based on viologen modified high-surface area TiO2 electrodes (Vio2+/TiO2) has moved the technol. towards commercialization. Viologen mols. (Vio2+), derivatized with phosphonic acid attachment groups can be chemisorbed on nanostructured TiO2 layers of thickness 2-10 μm. Characterization by cyclic voltammetry, spectroelectrochem. and impedance spectroscopy demonstrates that colorless Vio2+/TiO2 is reversibly reduced to the strongly colored cation radical species Vio+•TiO2. This system can constitute the working electrode of an electrochromic display with a capacitive doped SnO2 electrode as counter electrode, the latter coated by an electrochem. inert white light-reflecting layer. Such a device is stable upon repeated coloration-bleaching cycles with a bleached-to-colored state contrast ratio exceeding 5. Multicolor displays can be achieved by patterning different electrochromophores onto different areas of one working electrode

Light-induced electrolyte improvement in cobalt tris(bipyridine)-mediated dye-sensitized solar cells

Lithium-ion-free tris(2,2′-bipyridine) Co(ii/iii)-mediated electrolytes have previously been proposed for long-term stable dye-sensitized solar cells (DSSCs). Such redox systems also offer an impressive DSSC performance improvement under light soaking exposure, manifested by an increase in photocurrent and fill factor without the expense of decreasing photovoltage. Kinetic studies show that charge transfer and ion diffusion at the electrode/electrolyte interface are improved due to the light exposure. Control experiments reveal that the light effect is unambiguously associated with electrolyte components, [Co(bpy)3]3+ and the Lewis-base additive tert-butylpyridine (TBP). Electrochemical and spectroscopic investigation of the [Co(bpy)3]3+/TBP mixtures points out that the presence of TBP, which retards the electrolyte diffusion, however causes an irreversible redox reaction of [Co(bpy)3]3+ upon light exposure that improves the overall conductivity. This discovery not only provides a new strategy to mitigate the typical Jsc-Voc trade-off in Co(ii/iii)-mediated DSSCs but also highlights the importance of investigating the photochemistry of a photoelectrochemical system. Funding details: China Scholarship Council, CSC; Funding details: Energimyndigheten; Funding details: Vetenskapsrådet, VR; Funding text 1: We gratefully acknowledge the Swedish Research Council, the Swedish Energy Agency as well as the China Scholarship Council (CSC) for nancial support. The authors also thank Dr Lei Wang for his helpful assistance in 1H-NMR spectroscopic studies.</p