Hardware Projects

Project Halo

3D Printed Wooden Smart Ring

Summer 2016

In June 2016, I decided to propose to my now-wife in August of that year. I didn’t want to go the usual metal-mounted rock route and thought she might appreciate something more custom-made. Initially I thought I’d just build a ring with an attached LED matrix reading “Will you marry me?,” but then realized I might actually be able to fit a full-blown graphical display and some processing power into a ring form factor.

So over the next 1.5 months, I designed and built a 3D printed wooden smart ring.

On the software front, I created an operating environment for apps, with a home screen app launcher, and a media viewer that displayed hundreds of photos/videos of us from ring’s built-in MicroSD card. To enable the latter, I had to create a desktop app to convert media (photos, videos, and Microsoft / Nokia Living Images (same thing as Apple Live Photos, but earlier)) into a format that the microcontroller could process. I also customized some games that others had created, to feature my now-wife as the protagonist of each (Flappy Bird, Pong, Space Invaders, etc.).

The physical design was quite a challenge. I wanted something that looked like a ring, as compact as possible, but with as large a screen as I could fit, sufficient processing power and battery capacity, a standard charging interface, and modular construction (no sealed components). There would be a power slider and four buttons, and I needed to achieve a reasonable tactile experience on a very small device, within the resolution constraints of FDM 3D printing.

The final ring features a 0.96″ color OLED screen, Arduino-compatible 48 MHz ARM-powered processing hardware (TinyDuino), 16 GB MicroSD storage, and a 150 mAh battery yielding a few hours of runtime (charged via MicroUSB).

I printed and tested over 15 physical prototypes before finalizing the exterior design. I used wood composite PLA filament on my M3D Micro printer for the ring body, buttons, and power slider; some Swarovski crystals for a jewelry-esque touch; laser-cut acrylic for the screen surface; and gold paint to cover most of the exterior and give a slight antique look to the ring.

Contact me if you’d like to create a custom smart ring of your own!


Project Star Wars

LED-Lit Bhangra Khunde

Fall 2014

In law school / business school, I led and choreographed a series of bhangra dance performances at Harvard Business School’s annual South Asian cultural show, EKTA. For the fall 2014 show, I planned an additional element for our EC Bhangra performance, which I called “Project Star Wars.”

A khunda is a ~5 foot long stick, typically of lightweight construction, that is used in various ways in a bhangra performance. I decided I wanted to make khunde lit with LEDs throughout. To achieve this, I designed and built the khunde using:

  • Clear acrylic tubes (5 ft length, 3/4″ outside diameter, 1/16″ wall)
  • Blue LED light strings (with AA battery holder and power switch)
  • Metallic gold-colored polyester fabric

I cut the fabric into squares, which were attached to either end of each khunda; this made for a traditional look and also helped hide the battery holder / switch box.

In February 2015, the entire dance group met with HBS Dean Nitin Nohria, and we presented him one of the LED Khunde.


Robots

Semi-Autonomous / Teleoperated Robots

2003 – Present

Over the last 16 years, I’ve built a few iterations of a relatively compact (<20″ long) semi-autonomous robot (with basic path planning / obstacle avoidance + teleoperation). These have all had:

  • Full onboard x86 PC (VIA EPIA Mini-ITX -> Intel NUC)
  • Microcontroller (OOPic-R -> Netduino / Arduino)
  • Servo-mounted camera (Unibrain Fire-i -> Logitech C920)
  • World-scale localization sensors (GPS, compass)
  • Nav localization sensors (sonar / infrared rangers)
  • Built on top of treaded base platform (e.g. Heng Long R/C tank) with customized motors, gearbox, etc.
  • Battery capacity up to 100 Wh (NiMH -> Li-ion)
  • Remote operation over Wi-Fi using custom software (BotWare)

Urban Bicycles

Boston Commute-Ready

2013-2016

While in law school / business school, I had to shuffle between classes at the two schools. The fastest means to do so in Boston was by bicycle, but I soon realized that both (a) night-time visibility and (b) being seen by car/truck drivers were issues. So I added a bunch of parts to my bike, while trying to keep it as inconspicuous as possible when off (to dissuade thieves), to create an ideal (for me) urban bike for cities like Boston:

  • Full-suspension mountain bike [necessary for large potholes + winter road conditions]
  • High- and low-beam headlights
  • Taillights with laser-projected safety margin “lane” on road
  • Loud electronic horn
  • Motion-sensitive alarm [added in v3 after theft of v2 bike]

Synchronus

Wi-Fi-Connected Smart Alarm Clock

2009

For a class project in college, I designed and built a smart Wi-Fi-connected alarm clock, featuring web-based alarm scheduling, custom MP3 alarm sounds, auto-dimming display, temperature monitoring, and more. The clock was powered by dual Arduinos. The web control panel mockup above was by teammate MJ Truong.