Daniel Weeks Portfolio

University of California, Berkeley

College of Engineering

Mechanical Engineering

MS May 2016 | BS May 2017

Carousel Loading Tray• Problem:

– Design project for Accel Biotech.

– Design, prototype, and set up manufacturing for a loading tray for a rotary cartridge analyzer.

– Loading tray must hold cartridges in place when carried, but they must be inserted and removed easily. When the tray is inserted into the system, it must sit in the same location every time.

• Process:

– Design a model on Solidworks, 3D print it, and test with a 3D printed cartridge. Then iterate.

– Consult injection molders and machinists about manufacturability.

• Solution:

– Two-piece design, with the top injection molded (3D printed for prototype system), and the bottom

machined out of Delrin.

– T-shaped interface with the base plate, with a

locking spring to ensure consistent placement.

Robotic Copycat Arm• Problem:

– Senior group design project for Mechatronics Design.

– Students were encouraged to choose projects that integrate electronic and mechanical components.

• Solution:

– Build a robotic arm that is operated with an intuitive three-dimensional controller and a pressure-sensitive bulb to control finger movement.

– An Arduino translates the arm’s encoder readings to arm servo positions using reverse kinematics.

• My Role:

– Lead CAD design of the arm in Solidworks, and refine the model over the course of the semester, as the team participates in design reviews and performs stress analysis.

– Assist with machining of custom parts, as well as assembly and testing of the controller.

Snap Handle Valve• Problem:

– Design project for Parker Hannifin, Veriflo Division.

– Design, prototype, and test a valve that snaps and locks in the open and closed positions, and that can compete with competitors’ costs.

• Process:

– Two engineers each create a prototype and test them side-by-side.

– My partner created a more traditional design, using concepts and mechanisms already used in industry, and I pursued a new design idea.

• Solution:

– Both designs were built and tested side-by-side for snapping and sealing pressures at the end of the summer.

– My design sealed at over twice the required pressure rating.

Bionic Retriever• Problem:

– Final group project for Design of Planar Machinery.

– Electric wheelchair users often hang a backpack from the back of their chair, but cannot reach the bag or its contents without help.

– Existing wheelchair storage systems limit mobility, provide minimal storage, or are difficult or impossible for the user to access.

• Solution:

– Design and build an automatic four-bar mechanism that carries a backpack from the back of the chair to the armrest by pivoting around a roller.

• My Role:

– Build a CAD model of the chair in SolidWorks.

– Machine the metal pieces of the mechanism, assemble it, and mount it to the back of the chair.

Wheelchair Redesign• Problem:

– Semester group project for Introduction to New Product Development.

– The design of wheelchairs has seen very few changes in the last century. They remain bulky, difficult to use, and prohibitively expensive while providing very limited mobility to users.

• Process:

– Iteratively identify needs through customer and user interviews, generate concepts, and create prototypes to evaluate those concepts.

– Target active young adults who work or attend school in an urban college campus environment.

• Solution:

– Build a modular chair that can meet the varied

needs of users.

– Design additional products that are compatible

with the chair.

– Compose an intuitive web platform for designing

a chair and selecting the parts that fit a user’s

individual needs.

Optical Microphone Equalizer• Problem:

– Final project for Introduction to Mechanical Systems for Mechatronics.

– The frequency response of an optical microphone is uneven, with a much higher response at mid-range frequencies and a low response at high- and low-range frequencies.

• Solution:

– Design an equalizer in LabVIEW to create uniform loudness over frequencies from 100 Hz to 10 kHz.

– Use low- and band-pass filters to split

the input signal into frequency bands

and apply a gain to each frequency

band.

• My Role:

– Using data gathered from the

microphone’s natural response, choose

the corner frequency and gain for each

frequency band.

– Debug and modify the LabVIEW VI’s

used to test the equalizer and the

equalizer itself.

FDM Viscometer• Problem:

– Project for Engineering Design and Analysis.

– Design a viscometer in SolidWorks that, when 3-D printed, can measure the viscosity of a fluid using a vice with a position sensor and a compressive force sensor.

• Solution:

– Build a piston and cup viscometer with a rectangular base.

– Assume a linear flow profile to calculate the viscosity of the fluid.

– Two hinged flaps with a slot keep the plunger aligned and allow for easy removal and cleaning.

– Voted Best Design by the students and Graduate Student Instructors.

Albatross Aerodynamics• Problem:

– Final project for Engineering Aerodynamics.

– The white albatross glides just above the water for long distances without flapping its wings. See if it is possible to make a statement about its wing shape in relation to estimated induced drag.

• Solution:

– Approximate the albatross’ drooping wings as a half ellipse, with the tips of its wings almost touching the surface of the water.

– Using MATLAB, model the bird’s wings as strings of vortices and calculate the induced drag on the bird given various height-to-width ratios for the wings.

– For a 7-kg albatross able to withstand a moment of 18 N∙m at each wing, the optimum height-to-width ratio for a white albatross’ wings is 1:4, which is consistent with photographs.