K'NEX Computer

Fall of my junior year I began work on logic gates made out K'NEX using a system of balls. Two members of my Computer Architecture class joined me and we set out to create an entire 4-bit computer. The picture above is of a 4-bit adder.

There are more photos and updates at knexcomputer.blogspot.com

Inverted Pendulum

This is a project from a math and physics course my first semester in college. We were asked to model a second-order system. My group chose to model an inverted pendulum on a cart. After deriving and validating the equations of motion, we decided to implement a control system to keep the pendulum balanced.


After the class was over, I spent a weekend building a real version out of Legos to test our control system. It turned out that the 'best' parameters were not as good as the model predicted, but it did predict failure regions accurately.

This video shows working system. The pendulum itself has very little friction, both in the joint, and on the track. I used a potentiometer to sense angle, and I calculated angular velocity by having the pendulum back-drive a motor.

The control system was created in Simulink. The control circuit involved op-amps in negative feedback. The computer controlled the circuit using the very annoying Simulink Real-Time target and a flaky PCMCIA data acquisition card from Measurement Computing.

Lego Sumo Robot

I was one of 100 high school juniors accepted to the New Jersey Governor School of Technology. During part of the month-long program at Rutgers, we made robots from the Lego Mindstorms kit. The final robot project was a sumo wrestling match. Two robots would face off and attempt to push each other out of the ring. The robots could use light sensors to detect the edge of the ring, and had to start at size smaller than 10x10x10cm.

My team's robot (on the right) was the biggest of the 20 in the contest. It used two large, high friction wheels driven by worm gears to prevent back-driving. In the front it had vertically mount treads designed to lift an opponent off the ground, stealing its traction. It also had a telescoping arm that shifted the center of mass of the robot back over the wheels.

The robot was unstoppable when faced head-on, but was vulnerable when turning. In the final match, even though we knocked our opponent off in the first round, they beat us in the next 2 rounds by pushing from the side. We came in second.