[Thesis] D. Ha. (2013). Development of Microfluidic Chips and a Customised Flow Control System for use in a Label-Free Cytometer (*pdf). Electrical & Computer Engineering, University of Alberta. Edmonton, AB.

[Poster, awarded best conference poster] D. Ha, M. Gupta, M.Z. Islam, Y.Y. Tsui, X.T. Su, L. Marquez-Curtis, A. Janowska-Wieczorek, W. Rozmus. Wide-angle label free cytometry for the identification and sorting of biological cells. University of Alberta Graduate Residence Symposium. May 07, 2012. Edmonton, AB.

[Poster] D. Ha, M. Gupta, K. Singh, X. Su, M.Z. Islam, W. Rozmus, Y.Y. Tsui. Wide-angle label-free cytometry using light scattering. CYTO, XXVI Congress of the international society for advancement of cytometry. May 21-25, 2011. Baltimore, MD, USA.

[Poster & Oral Presentation, awarded best oral presentation] D. Ha, M. Gupta, M.Z. Islam, K. Singh, J.N. McMullin, Y.Y. Tsui, X.T. Su, L. Marquez-Curtis, A. Janowska-Wieczorek, W. Rozmus. Label-free microfluidic cytometry for the characterization of single biological cells. CIPI, Canadian institute for photonic innovations. May 18 -20, 2011. Ottawa, ON.

M.T. Taschuk, M. Gupta, Y. Zhou, D. Ha, et al. (2011) Portable Hydrocarbon Sensor for Environmental Applications (*pdf), 56-58. In CIPI Photons.    

Summer 2008

My interest in controls and robotics stems this design project that I completed as part of my undergraduate education. We were supplied with basic electronics, an AtMega8501 microcontroller, 12V batteries, a wooden base with wheels, and tasked to create a delivery robot that would navigate a fixed course autonomously. The robot was also required to push buttons and enter a simple elevator to reach the goal. Sensors could be mounted onto the robot to enable it to respond to physical stimuli (such as detection of walls) or a predetermined set of actions could be dead reckoned into the software.

The motor driver, sensors, and software for my robot worked perfectly when tested on their own. However, when all components were tested together, unexpected interactions between the programming of the microcontroller and motor driver caused the robot to malfunction. KRAKATOA lived up to its explosive name and short-circuited its FETs in a fiery blast during last minute testing.

This was my first disappointing taste of real engineering design. But rather than discouraging me, the knowledge that I gained from this failure fired up my desire to continue creating, building, and failing (if need be) to learn more. After all, theory can only teach us so much, after which, hands-on experience takes over.

Fall 2009                                                             

In fulfilment of Dalhousie University’s Senior Year Design Project, this project improved upon Satlantic’s existing analog Photosynthetically Active Radiation (PAR) sensor by converting the existing analog output to a digital output, and by adding a tilt-sensing module

Winter 2009

Our objective was to design, build and test a stable RF amplifier to operate in the 1.93 to 1.99 GHz frequency band. The amplifier had to have an overall gain greater or equal to 18dB, minimum noise figure less than or equal to 2.3dB, and input and output return loss greater than or equal to 10dB. Source and load impedances were specified at 50Ω. We were able to use software such as ADS to simulate the desired specifications then build the actual amplifier on a PCB.
                               

This project is very tricky. More often than not, the simulation software contradicts the real thing and real world factors such as coupled inductances on a PDB get in the way of producing gain. In my class, my group was the only one to successfully build an amplifier- other groups ended up with attenuators and oscillators instead.

In general, the amplifier performed nearly to our expectations. The fact that we were able to get an acceptable gain of 10dB, while still below spec, was very promising. The implementation could be tweaked further to improve the results somewhat beyond what we were able to achieve. Designing the amplifier was a rewarding and educational process that exposed us to the process of designing amplifiers in real life.

Fall 2008

J. Josefowicz, & D. Ha, LED Roadway Lighting Ltd. (2008)  Vision & Exterior Lighting: Shining Some Light on Scotopic & Photopic Lumens in Roadway Conditions (*pdf). Halifax, NS. White paper reviewed and approved by Dr. Samuel M. Berman.

This white paper was written during my co-op work term for LED Roadway Lighting Ltd. in conjunction with Dr Jack Josefowicz and approved by lighting specialist Dr Samuel Berman.                               

The LED light spectrum was compared to that of a conventional streetlight and the whiter spectrum of the LEDs was proved to be more advantageous to nightvision as compared to the warm orange glow of most conventional streetlights. It was written to fill a gap in industrial knowledge on the interpretation of roadway lighting standards as some LED companies were reducing their overall light levels below standard lighting specifications to promote higher energy efficiency levels, on the erroneous assumption that scotopic lumens could be added to photopic lumens. Being the only paper clarifying this fact and catering specifically to LED lighting, it received quite a lot of attention in industry.

More detail can be found in the white paper, available for download or from the LED Roadway Lighting Ltd. website.

Fall 2007 

The objective of this project is to build a self-starting DC rotor only with the supplied material- a plastic film canister, a strip of metal, a strip of copper, a wooden spool, metal axle, and magnet wire. When connected to power, it should create a motor that runs at 1200 rpm for 5 min at 12V, max 6A.

My design was admirable in spirit but a little too ambitious to implement due to manufacturing challenges. Thus, our motor only ran when supplied with 12 A at 12V. Even then, it required a spin to start and ran at much less than 1200 rpm. This is due to 3 critical errors in our design and construction – cogging due to the misalignment of laminated steel fins, winding loops that were not sufficiently skewed, and a probable short in the windings.