Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: The computational power of mobile smart-phone devices are ever increasing and high-end phones become more popular amongst consumers every day. The technical speci cations of a high-end smart-phone today rivals those of a home computer system of only a few years ago. Powerful processors, combined with cameras and ease of development encourage an increasing number of Augmented Reality (AR) researchers to adopt mobile smart-phones as AR platform. Implementation of marker-based Augmented Reality systems on mobile phones is mostly a solved problem. Markerless systems still o er challenges due to increased processing requirements. Some researchers adopt purely computer vision based markerless tracking methods to estimate camera pose on mobile devices. In this thesis we propose the use of a hybrid system that employs both computer vision and integrated sensors present in most new smartphones to facilitate pose estimation. We estimate three of the six degrees of freedom of pose using integrated sensors and estimate the remaining three using feature tracking. A proof of concept hybrid system is implemented as part of this thesis. / AFRIKAANSE OPSOMMING: Die berekeningskrag van nuwe-generasie selfone neem elke dag toe en kragtige "slim-fone" word al hoe meer populêr onder verbruikers. Die tegniese spesifikasies van 'n nuwe slim-foon vandag is vergelykbaar met die van 'n persoonlike rekenaar van slegs 'n paar jaar gelede. Die kombinasie van kragtige verwerkers, kameras en die gemaklikheid waarmee programmatuur op hierdie toestelle ontwikkel word, maak dit 'n aantreklike ontwikkelingsplatform vir navorsers in Toegevoegde Realiteit. Die implimentering van 'n merker-gebaseerde Toegevoegde Realiteitstelsel op selfone is 'n probleem wat reeds grotendeels opgelos is. Merker-vrye stelsels, aan die ander kant, bied steeds interessante uitdagings omdat hulle meer prosesseringskrag vereis. 'n Paar navorsers het reeds rekenaarvisie-gebaseerde merker-vrye stelsels aangepas om op selfone te funksioneer. In hierdie tesis stel ons die ontwikkeling voor van 'n hibriede stelsel wat gebruik maak van rekenaarvisie sowel as geintegreerde sensore in die foon om die berekening van kamera-orientasie te vergemaklik. Ons gebruik geintegreerde sensore om drie uit ses vryheidsgrade van orientasie te bereken, terwyl die oorblywende drie met behulp van rekenaarvisie-tegnieke bepaal word. 'n Prototipe stelsel is ontwikkel as deel van hierdie tesis.

The monitoring of pharmaceuticals, heavy metal, pH and free chlorine concentration in drinking water is important for public health and the environment. However, conventional laboratory-based analytical methods are labor-intensive, expensive, and time consuming. This thesis focuses on developing an integrated, highly sensitive, easy-to-use, and low-cost pharmaceuticals, heavy metal, pH and free chlorine sensing system for drinking water quality monitoring. A low-temperature, solution-processed modification of multi-walled carbon nanotubes (MWCNT) with β-cyclodextrin (βCD) on glassy carbon electrode is developed for detecting low levels of acetaminophen. The adsorption properties of βCD are combined with the high surface area of carbon nanotubes towards enhanced electrochemical sensing of acetaminophen with a limit of detection of 11 nM and linear range from 0.05-300 μM. Also, a systematic investigation is carried out using four types of modified MWCNT-βCD. A novel, one-step approach called Steglich esterification modified MWCNT-βCD results in large effective surface area, and fast electron transfer towards sensitive detection of acetaminophen and 17β-estradiol (E2, primary female sex hormone) in the range of 0.005–20 and 0.01–15 μM, with low detection limits of 3.3 and 2.5 nM, respectively. The similar MWCNT-βCD modified electrodes can also detect heavy metal ion (lead, Pb2+) with a limit of detection of <10 ppb. Low frequency noise behavior of these sensors are studied. A spin-coated Pd/PdO based pH sensor, and amine-modified carbon electrode-based free chlorine sensor are fabricated on a common substrate together with the pharmaceuticals and heavy metal sensors. A Wheatstone-bridge temperature sensor is fabricated based on silicon and PEDOT:PSS on another substrate. All the sensors are connected to an Arduino microcontroller based data acquisition system with a smartphone application interface. The integrated sensing system is easy-to-use, low-cost, and can provide accurate monitoring data with real drinking water samples. / Dissertation / Doctor of Philosophy (PhD) / Low-cost, easy-to-use, and sensitive monitoring system for pharmaceuticals, heavy metal, pH and free chlorine in drinking water is crucial for public health safety. In this thesis, we develop solution-based synthesis of multi-walled carbon nanotubes modified by β-cyclodextrin for electrochemical sensing of pharmaceuticals and heavy metal. The modification approaches are compared and characterized to analyze their electrochemical behavior and sensing performances. The developed sensors are highly sensitive toward the detection of acetaminophen (a widely used pain-killer) and estrogen hormone in drinking water. We also develop a modified spin-coating technique to deposit palladium/palladium oxide films for potentiometric pH sensor, a calibration-free free chlorine sensor based on modified carbon electrode, and a resistive temperature sensor. The developed pH, free chlorine and temperature sensors are highly sensitive, and stable with fast response time. All the sensors are integrated and interfaced with a custom-made and smartphone-controlled electronic readout system for accurate and on-site drinking water quality monitoring at low cost.