IR / Optical Relative Positioning System Oct 2011 - Jan 2012

As a semester project working with the EPFL Biorobotics Laboratory, I designed, built, and tested a relative positioning system for mobile robots that uses modulated infrared or visible light to determine the range and direction to a modulated source. The sensor is insensitive to ambient light differences and other environmental factors. The system also allows low bandwidth communication and can be used to detect obstacles (using an onboard transmitter). The device is smaller than existing systems, and be easily adjusted to suit new environments.

prototype transceiver

first hardware revision

circuit board layout

block diagram of receiver

distance calibration

detector sensitivity

Collaborators: Dr. Alessandro Crespi, Dr. Juke Ijspeert (faculty)
Files: final presentation, report, circuit schematic
Tags: relative positioning, circuit design, SPICE simulation, filter design, embedded systems, infrared and optical communications, EPFL
Simulated Robotic Salamander Sept 2011 - Jan 2012

As a laboratory project for my Models of Biological Sensory-Motor Systems course, we investigated the locomotion and control of a 23 degree of freedom simulated salamander robot. We examined the different parameters controlling both walking and swimming using a sine-based controller and a central pattern generator (CPG). We found that, when optimizing the average speed through systematic tests and particle swarm optimization, the optimal gait and swimming trajectories are similar to the movement of actual salamanders. We improved our salamander model by adding stereovision and, using a biologically-inspired vision system with a neural network, created an autonomous salamander capable of tracking and walking toward objects.

walking salamander model

comparison of actual salamander and optimized controllers


configuration of central pattern generator model

transition from walking to swimming

Collaborators: Frédéric Wilhelm
Files: draft report
Tags: robotics, salamanders, robotic controllers, central pattern generators, particle swarm optimization, visual system, Webots, EPFL
Autonomous Board Cleaning Robot Jun 2011 - Aug 2011

During the summer of 2011, I worked in the Self-Organizing Systems Research Group at Harvard University. While there, I developed MAG-NEATO – an autonomous board cleaning robot. I designed the hardware and circuitry, sourced materials, machined parts, assembled the system, and programmed a series of autonomous behaviors. The sub-$100 robot features custom magnetic wheels, a 32 MHz microcontroller, LED indicators, input buttons, an accelerometer, bump sensors, reflective color sensors, an integrated battery charger, and an expansion port.

engineering model of MAG-NEATO

exploded view

magnetic attachment

top view

bottom view


erasing whiteboard

Collaborators: Dr. Radhika Nagpal (faculty), Dr. Nils Napp
Files: presentation, circuit schematic
Videos: demo, magnetic attachment
Tags: autonomous mobile robots, education, circuit design, C programming, Atmel AVR, system integration, Harvard University
Force-Sensitive Multitouch Surface Feb 2011 - May 2011

As a research project during the Spring of 2011, I worked with several other students to develop a force-sensitive multitouch surface. We built a functioning prototype and tested a series of different compliant surface materials which allowed us to estimate the pressure caused by objects and touches.

FTIR multitouch surface (source: Ars Technica)

preliminary results

Collaborators: Jacob Ghetto, Timothy Raymond, Seungwhan Moon, Dr. Mark Chang (faculty)
Tags: compliant surface materials, frustrated total internal reflection (FTIR) multitouch, Olin College

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