[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.
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
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
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.
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.
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,
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.