Selected Research Projects
[ GECO ]
I was responsible for actuation on a tactile feedback system going into the new NASA space gloves, dubbed Glove-Enabled Computer Operations (GECO). Working with a team of engineers, we developed specifications for rendering a diverse set of sensations on astronauts' fingers, and strategy to meet those specifications. I designed and built the system using a 3D printer. The result is now being tested at Johnson Space Center, and has been published at the International Conference on Environmental Systems.
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[ Metamaterial Design ]
Metamaterials are a new class of material engineered to have properties that do not exist in nature. However, designing metamaterials is complex, and no system currently exists to help engineers create them. To solve this problem, we built a CAD system that generates the structure of a metamaterial based on stiffness gradients. I was asked to contribute mathematical models that let the software convert user input into 3D structures with the target behavior. The successful result is currently under review at the Conference on User Interfaces and System Technology (UIST) and serves as the basis for advanced work on metamaterials in the lab.
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[ ISM ]
I was asked to lead the team responsible for a solid-state weather station with no moving parts that could be built for <$100 and would last 10 years. I began by building a mathematical model of the proposed system to shorten the number of prototyping cycles and determine the limits of our dynamic design. I used this model to develop specifications for our electrical engineer, who I helped to find and hire. With the founder, I developed a project timeline and deliverables. I coordinated software development, electrical engineering, and mechanical engineering to ensure the timeline was met. I managed all aspects of the design, and was principally responsible for the concept, simulation, and mechanical engineering. In addition, I collaborated with vendors in injection molding and machinists to ensure the final product could be manufactured cheaply at scale. The result was a system built to be cheaper and more accurate than competing products and ready for outdoor testing and early manufacturing runs.
[ An Ear for Rain ]
In my role as lead on ISM, I was responsible for a novel acoustic rain sensor. I started by testing scrap metal parts picked up from a local hydroformer that fit the design guidelines of the large weather station, measuring their impluse response with a piezo. I used simulations of rain to specify the sensor dimensions, and adjusted the prototypes. I expected that a rigid structure would work best, believing high fidelity transmission to be the most important quality. However, tests with softer materials worked better. This changed my perspective, and I began to think of it as an impedance matching problem. Working with our electrical engineer and machinist, I redesigned the sensor as an impedence matcher and prototyped another round. Tests I ran with LabView code I wrote confirmed the improvement in sensitivity I had expected. Additional simulations of rain I gathered from scientific literature were used to improve accuracy futher. The resulting sensor could track rain with the resolution of a single drop, was self-cleaning, and measured rainfall with a microphone and no moving parts.
[ InnerSol ]
InnerSol is a sensing system that tracks and manages the life of plants. It grew out of my interest in food systems and sustainability. I led the team that designed it, and was responsible for the concept, mechanical design, embedded software design, prototype construction, and sensor testing. The successful project sensed soil moisture and light, combined this data with a plant's state, and sent the updated state to a server. The server side pushed data to a mobile phone, and transfered commands to run actuators. By running pumps and lights, InnerSol could autonomously manage a garden.
[ Deltafish: Concept Electric Car ]
The Deltafish is an experimental prototype electric vehicle I designed and built to investigate the feasibility of wheel hub motors driven by independent controllers. At the Deltafish’s inception, no manufacturers had demonstrated wheel hub motors in a four wheel vehicle, giving universal preference to centralized motors and transmission systems. Over the course of a year, I designed the chassis and drive system, recruited and led the team of machinists that helped build it, and ran testing. The successful system achieved over 2g's of acceleration on its way to a top speed of 35mph.
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[ Tactile Impedance Adapter ]
I was asked to build a mechanical coupler that greatly increased the energy transfer between a tactile motor and the human skin. I started by combing the research literature for work on the impedance of the skin, which I used to design a simulation. I used that to optmize a coupler design that I built and tested with human subjects. The system quadrupled energy transfer by matching the impedance of the skin, and resulted in two scientific publications. This was the first time these techniques were applied to haptics.
[ ShiftPad ]
Our computer systems have been able to deliver an exponentially increasing quantity of information since Moore's Law began. However, the basic audiovisual interaction modality has changed only marginally since the introduction of the mouse. The ShiftPad opens up new avenues of communication by incorporating force-feedback into human-computer interaction. The user places her hand on the middle pad, and moves the cursor by tilting. The computer sends signals back by adjusting the current to motors mounted on each axle, effectively producing the sensation that the cursor is moving up and down over the screen. This allows users to feel the edge of the screen, accurately target buttons, and feel the contours of images on the screen. My Contribution: Concept development, mechanical design, parts acquisition.
[ MouseBot ]
MouseBot is a bio-inspired robotic platform to designed explore the dynamic behavior of small animals, and investigate how this behavior could inspire new modes of robotic perception. The robot use a TI MSP430 microcontroller as its central nervous system, and applies a simple computer vision system to perceive the world. The vision system combines a stream of depth information with the careful application of differential motor drive to determine the robot’s heading in relation to nearby walls. This basic sensory system provides the capacity to avoid obstacles and evade pursuers, giving MouseBot a basic artificial intelligence. My Contribution: Team lead, concept development, algorithm design, embedded software architecture, testing.
The yoga clip is designed to monitor compliance in medical studies on the benefits of yoga. Designed for the University of Washington Department of Nursing, the device needed to track when the mat was in use, easily connect and disconnect from a yoga mat, and be robust to rough handling, The clip uses a light sensor to recognize when the mat is rolled and unrolled. My Contribution: Mechanical design