Katy Kem

The title of my M. Eng. thesis is Laboratory Assignments for Teaching Introductory Signal Processing Concepts. The abstract of my thesis is as follows.

This thesis proposes labs for a new, applications-based signal processing class. These labs span topics in audio, image, and video processing and will combine signal processing techniques with computational tools. The goal of these labs is to improve student understanding of signal processing concepts and show them the power of signal processing in everyday applications.

The labs I've designed for this class include: a chord detection lab, a musical fingerprinting lab, a JPEG compression lab, and a video movement magnification lab. For a PDF of the Introduction and Conclusion of my thesis click here. These lab assignments will be used in an actual MIT signal processing class, so I haven't included the chapters detailing the labs themselves as students could find them and use them to skip to the solutions of the assignments. If you're interested in more details about my thesis and the labs themselves, please contact me directly.

When I joined Lumafield in September 2020 it was only 15 people and still based out of Greentown Labs in Somerville. Since then the company has grown to ~65 people on two coasts and I’ve been with our product - the Neptune CT Scanner - from the alpha prototype through the our production run.

My first 16 months at the company I was the only Electrical Engineer, and I did it all. I designed the entire electrical system for our beta prototype unit. Our EE team grew to 2

I’ve rapidly prototyped new design concepts, often in conjunction with Mechanical Engineers. I’ve single handedly designed several PCBAs of varying complexity, taking them from concept through schematic and layout. I’ve designed all the cabling and spec’ed all the other electrical components in our system. I’ve worked with the Mechanical Engineering team to make sure said electronics are well integrated with the rest of the system. I’ve worked with a firmware contractor who wrote the basic framework for our system’s firmware. I’ve implemented nearly all of the firmware features we’ve added and enabled since then. I’ve accompanied our product to an FCC testing facility and made on-site improvements to get it to pass certification. I’ve mitigated supply chain issues during the ongoing chip shortage.

I’ve had the pleasure of working with incredible engineers on a multidisciplinary team to take our CT scanner ready for production manufacturing!

I was the main EE on a Vivint camera project while it was still under development. Here are some of the things I did for this project.

I wrote & implemented the test plan for the first PoC of the product. This included evaluating the efficiency of the entire power tree of the device. In order to reduce the power consumption to improve the thermals, I redesigned much of the power tree to be more efficient, and used simulation tools (LTspice, etc) to check the improvements. These changes should take over 1W out of the system, which is a big deal for a product like this!

At Vivint, we partnered with a third party company in Taiwan to jointly develop the product. I had to communicate and work remotely with this team in order to get the design we want. This involved much back & forth communication with plenty of documentation for both the schematic and layout of the board. The layout in particular I give a lot of feedback on to ensure that the product will have high signal integrity, low emissions, and good power delivery. Through Vivint, attended a two-day course called “PCB2Day” in order to learn the essentials of good PCB design.

The electronics of the product do not operate withing a vacuum. I’ve had to work closely with the firmware engineers, mechanical engineers, and industrial designers on the project to make sure all the pieces come together to create a good product.

For my Product Design Engineering (2.009) class, I was on a team of 25 people and our goal was to create an Alpha prototype of a consumer product. We created an automatic IV pole that follows the patient around hands free.

As this was a mechanical engineering capstone class, I was one of only two electrical engineers on the team. I led the electrical subteam of about 6 people, and together we made the thing work! In addition to my management duties I also took charge of sensor integration, the power module, designed the central brain PCB, and did much of the electrical assembly.

How it works: The patient is already connected to the pole via IV tubes, and we add a small tether clipped to their clothing. This tether is connected to a string potentiometer and angle potentiometer, so the information about the patient's distance and angle to the pole is encoded. This information is collected by a microcontroller and sent to a Raspberry Pi running ROS which would use a pathfollowing algorithm to follow behind the patient (can't take credit for this one - the work of my fabulous EE team!). There were also several sensors integrated as safety mechanisms such as bump sensors and cliff sensors so the IV pole won't fall down the stairs or get tangled up in obstacles.

My final project for my Microcontrollers Lab Class (6.115) was a laser guitar. Instead of strings it has laser beams, and when you break the beam, it checks which frets you're holding down and plays that note. I designed built the guitar myself. Check out the video to the left for the full effect!
How it works:  I used laser diodes and phototransistors to create the "strings." When the user breaks the laser beam, the voltage across the phototransistor changes. The microcontroller senses this, then checks which fret is being held down and plays that note. The fret is sensed using a grid of 114 push button switches (which were a huge pain to solder). Each string corresponds to a different note, which are then added together and sent to the speakers so you can rock out in style!

I came up with a new product idea for Vivint (the smart home company I work for). It’s a sensor that attaches to your washing machine or dryer, senses when the laundry cycle is complete, then sends a notification to your phone when it’s done. I made a simple prototype using an arduino and an accelerometer. I tested it with my own laundry machine and recorded what the cycles look like with accelerometer data. I also built a miniature, desktop “washing machine” to simulate the movement so I could demonstrate it at work using an asymmetrically weighted motor in a box.

I conducted market research and customer interviews/research to see if it was something they’d actually be interested in. I then pitched and demoed my product concept and prototype to Vivint. They didn’t end up going for it, but the process was fun nonetheless!

As a skier, I hate when my feet get cold and am not satisfied by the boot heating products on the market right now. This product uses induction heating to wirelessly heat the inside of the boot!

How it works: Inside the ski boot is a small, thin insert. This insert has a thin, ferrous metal plate in the toe area. The user stands on a platform with an induction heater inside of it, which uses a switching magnetic field to send power to the small metal plate through the boot without any wires needed! The insert also has a small temperature sensor which sends the temperature back wirelessly via NFC (Near Field Communication). The system shuts off when the desired temperature has been reached and the user can step off the platform and continue skiing in comfort!

I built the original prototype for Power Electronics Lab (6.131). For my Product Design Engineering (2.009) class, I proposed this idea as a potential product. I led a small group of students as we pursued further versions of it, and ended up with a mockup of the product as seen in pictures here.

It's tradition on ski team to ski your final race senior year in costume. For our senior race my fellow seniors and I made our own stormtrooper costumes.

To make the armor, we hand sanded molds out of dense green foam and thermoformed the pieces with sheets of white plastic. We wore black morphsuits over our usual racing suits and attached the armor using a combination of Velcro, white duck tape, and a prayer. For the helmets we found a template online and lasercut cardboard. We assembled them using hot glue and painted them white, then fixed them onto our race helmets. To round out the effect, we painted our slalom shinguards white and carried around speakers blasting the Imperial March all day.

Inspired by the Afterglow Lightsuit video (click the link to watch you won't regret it!), my ski teammate Val and I decided to make our own lightsuit for night skiing! We got most of the supplies from Walmart and sewed the strings of LEDs on while different teammates modeled it. I soldered the strands together and sketchily waterproofed the large LiPo battery which we stashed in the pocket of the black sweatshirt. We got some decent footage, especially skiing Beacon Hill after one of Boston's infamous blizzards of 2015!

For my CMOS Analog Electronics (6.775) project, I had to design, and simulate an Op Amp using Cadence to meet certain specifications. To learn more read my paper!

For my Discrete Time Signal Processing (6.431) final project, I had to use MATLAB to characterize a noisy spectrum as well as create a spectrogram for a time-changing signal. Feel free to check out the reports! The spectrum characterization report is here and the spectrogram report is here.

For my Power Electronics (6.334) final project, I had to design, spec, and simulate a DC/DC converter using LTSpice. Feel free to check out my final paper attached here. Note: a few of the graphics are missing.

I love to make and create things, and that doesn’t end with engineering. I’ve been taking oil painting lessons for the past year or so, and have really enjoyed the creative outlet. Here are some of my paintings!

I love to make and create things, and that goes beyond just engineering! I took a sewing class two years ago, and have since used that skill to make all kinds of fun projects. I even made some cool reusable masks for the pandemic. I’ve also taught myself to knit and crotchet, and am currently in the process of completing a sweater. Just in time for mid summer heat!