Nameless Microwave gets Down N' Dirty[Video]

Things are moving fast for the RoboWargames team. In and out of UAT. The team (headquarters located in the 244 hardware lab) took their stock Parallax rover out for a spin yesterday after refueling it with both hydraulic fluid and gasoline. After a short warm up and a few minor hiccups the rover was soon getting carried away with itself. Under the control of a remote ofcourse. The max speed of the rover is ~15 mph but due to the hydraulic settings it was cruising at a good ~10 mph.

The rover will eventually be pimped out with a laser range finder, onboard cameras, various sensors, a sleek casing, and autonomous programming. It will be our entry into the IGVC (Intelligent Ground Vehicle Competition) in the summer of 2011.

Visual 6502 Processor Simulation

Greg James, Barry Silverman and Brian Silverman from Visual6502.org have been working for the last year on a transistor-level visual simulation of the 6502 microprocessor.  Their work is incredibly detailed and very interesting.  The 6502 design is a classic processor, and very important in computer history as it was used in the Apple I & II, Commodore, Atari and Nintendo computing systems.

In the summer of 2009, working from a single 6502, we exposed the silicon die, photographed its surface at high resolution and also photographed its substrate.  Using these two highly detailed aligned photographs, we created vector polygon models of each of the chip's physical components - about 20,000 of them in total for the 6502.  These components form circuits in a few simple ways according to how they contact each other, so by intersecting our polygons, we were able to create a complete digital model and transistor-level simulation of the chip.

Prizes for Electric Car Algorithms

The CREATE Lab at Carnegie Mellon University is sponsoring a contest to develop efficient battery-management algorithms for electric vehicles.  At the end of every month, high-performing entries will be awarded small prizes ($100 in Amazon gift cards), with a grand prize (possibly an actual electric vehicle) awarded at the end of the competition.  At the end of each monthly judging phase, entries are open-sourced for all to see and share.

Autonomous Battery Exhange

Researchers at Ecole Polytechnic in Lausanne have developed marXbot and snazzy battery exchange system. The batteries are modular and charge in a kind of ferris-wheel. When the robot runs low on juice, it docks with the station, and the dead battery is removed from the robot chassis by a manipulator. During the swap, robot power is provided by an alternate ultra-capacitor based system that can provide 15 seconds of power for the critical systems (i.e. only maintaining cpu memory state). The wheel rotates to a fresh battery, and the manipulator pushes it into the chassis, completing the hot-swap.

Graffiti Analysis Sculptures

Graffiti Analysis: 3D from Evan Roth on Vimeo.

Graffiti Analysis: Sculptures is a series of new physical sculptures that I am making from motion tracked graffiti data. New software (GA 3D) imports .gml files (Graffiti Markup Language) captured using Graffiti Analysis, creates 3D geometry based on the data and then exports a 3D representation of the tag as a .stl file (a common file format compatible with most 3D software packages including Blender, Maya and 3DS Max). Time is extruded in the Z dimension and pen speed is represented by the thickness of the model at any given point. I then have this data 3D printed to create a physical sculpture that serves as a data visualization of the tag. For the Street and Studio exhibition at the Kunsthalle Wein, I collaborated with an anonymous local Viennese graffiti writer and had the GA sculpture printed in ABS plastic. Graffiti motion data of his tag was captured in the streets (for the first time) at various points around Vienna.

More information (including software, source code, and many more pictures) can be found at Evan's website.

Self-Folding Origami

Robert Wood of Harvard University, Daniela Rus and Erik Demaine at the Massachusetts Institute of Technology take us to a new level of robotic creepiness with self-folding origami.  The device is able to morph itself into new shapes using shape-memory alloys that line the edges of triangular modules.  Each module also sports a strong magnet that holds the final form after a module has executed a desired fold.

3D Printed UAT Shadow Sculpture

Last week I built this shadow sculpture inspired by the cover of the Pulitzer-prize winning book "Gödel, Escher, Bach: An Eternal Golden Braid" this is a 3D-printed form that casts three orthogonal shadows in the shapes of the letters UAT.    After I printed it, I used some blue LEDs and foam-core to build a little display platform for it.

Here is the Inventor part file: UATCube.ipt

The Guardian: Inexpensive AVR-based Cat Food Protection

Over 6 months ago we added two kittens (Duke and Ella) to our household, and we found out that our dog, Riley was eating their food.  To prevent this, I built the Guardian, an AVR-based protection system that humanely keeps Riley away from the cat food, but is not triggered by the cats themselves.

I wanted this setup to be cheap, so I decided to use an infrared "trip-wire" system.  On one side of the hallway is an always-on infrared emitter, and on the other side is an infrared receiver, an AVR ATmega8 microcontroller, and a buzzer.  The micocontroller continuously checks to see if the beam between the emitter and receiver has been broken - if it has, it sounds the alarm, which Riley hates, driving him away.  The microcontroller is programmed so that small, fast things (such as cat tails) do not trigger the alarm.  Also, the whole rig is place at Rileys shoulder height, which is much taller than the cats bodies.

This may not work for most dogs, as Riley is a pansy and afraid of loud noises, but here are the schematics, source code, and a rough bill of materials:

Schematics (Eagle, PNG)
Source Code
Bill of Materials

3D Printed Tensegrity Structure

This weekend I built a Tensegrity structure as a demonstration of principles of balancing tension and compression in structures for my course RBT379 - Mechatronics.  I've been fascinated by the aesthetic of these structures - all triangles and edges, but somehow magical as your brain tries to wrap itself around the reasons why the solid supports seem to be floating in air, and the structure is still standing.

I found a couple of excellent pages documenting how the structures work and are assembled - one from the artist Kenneth Snelson explaining the aesthetic inspiration for Tensegrity structures as a kind of 3-dimensional weaving, and another more practical site detailing the construction of a Tensegrity coffee table.

I used the UAT 3D printer to make 12 struts.  You can make these out of much simpler materials (wood, copper, chopsticks, etc), but the Inventor Part design for the struts are provided here. A gallery of the build process and completed 3-level structure (and one rubber-band version) are below.

 I used 20lb test mono-filament fishing line and 2 sets of good smooth-jaw pliers to tie the knots (grip-jaw pliers scar the fishing line, causing breaks after you've carefully tied many little knots), following the guidelines at the Tensegrity coffee table website. If you do this yourself, construct a jig that will allow you to accurately create the tension links at a certain distance (the length of your struts divided by 1.4).

 I built 3 modules, 2 "left-handed" and 1 "right-handed."  To assemble them into the tower, I hooked the struts of one module into the base triangle of tension elements of another, forcing the base triangle into a hexagon.

The resulting structure is surprisingly sturdy, and the fishing line is somewhat transparent, adding to the mystical effect I was trying to emphasize.

ArcAttack: Ride the Lightning

I've always been fascinated by Tesla Coils. The operating principle is so elegant - you set up one circuit (your power supply) that oscillates at some high frequency, and you set up another circuit that uses the earth to resonate with your power circuit. Energy is transferred and converted from current to voltage, and the end result is man-made lightning - an incredible display of light and sound.

Newer versions of the Tesla coil allow the control of the resonant frequency.  Have you ever noticed the sound that a flourescent light makes?  That kind of "buzz" ? You're hearing the frequency of the power that is coming into your house (around 60Hz).  When you control the resonant frequency of the Tesla, you control the tone that it generates, and thus the Singing Tesla Coil is born.  This is not lightning set to music - the sound is generated by the spark itself.

The band ArcAttack has integrated a pair of singing Tesla coils into their repertoire, with epic results: