mysong (with ian and sumit)

MySong automatically generates chords to accompany a vocal melody, and lets a user with no knowledge of chords or harmony manipulate those chords with intuitive parameters. Songwriting for everyone!

superbreak (with a.j. and brian)

superbreak adds hands-free interactivity to traditional ergonomic break-reminder software.

searchbar (with merrie and gina)

searchbar is a browser history centered around search topics and queries, instead of the not-all-that-useful constructs like domain and date that current browsers use to organize web history.

muscle-computer interfaces (with scott, desney, and ravin)

Muscle-computer interfaces will someday allow users to directly control computer interfaces via muscle activity, without manipulating objects in the physically world. Our initial work in this space explores fundamental techniques for processing muscle activity.

surgical simulation

my phd work focused on haptics and physical simulation for virtual surgery, specifically on building an environment for simulating bone surgery.

neural prosthetics

i worked with cyberkinetics and brown on clinical neural prosthetics. I present some introductory concepts and code here.

chai 3d (with the chai team)

chai 3d is an open-source scenegrpah library for haptics and graphics.

evaluation of haptic rendering systems

standardized evaluation of haptic rendering systems is a data and analysis repository for evaluating the realism of haptic rendering.

haptic mentoring

This project explored the use of haptics to teach force-sensitive motor skills. More details are available in our WordHaptics paper.

algorithms and data structures for haptic rendering

this technical report describes a few haptics-related tricks used in my thesis work.

preparation, calibration, and simulation of deformable objects

This technical report describes some of my thesis work, focusing on calibrating interactive deformable models.

haptic battle pong (with neel)

voxelizer

voxelizer generates voxel arrays and internal distance maps for surface meshes. Technical information is available in the corresponding technical report.

winmeshview

winmeshview is a simple (and free) viewer and converter for 3d surface and tetrahedral meshes.

cs148: introductory graphics

I taught the intro graphics class at Stanford over the summer of 2005. The content is archived here.

life-sized candyland (with Augusto and Jeff)

we built a life-sized candyland game. cards are drawn using a clapper, and candy is dispensed to the winner in the epic game of strategy and skill. part of the third-floor's holiday extravaganza.

audio for collaborative environments (with merrie)

This project explored the use of private audio channels in single-display groupware systems, and was published in CSCW 2004.

tele-drawing (with neel and kirk)

a system in which a camera allows a user to tele-operate a robotic arm and draw inspiring two-color pictures.

hybrid rendering (with neel)

this project presents an approach to combining images raytraced offline with real-time graphics and haptic rendering.

haptic images (with neel)

a system that allows a camera to capture an image and render it haptically.

fitness racer

instructions on how to control a cheap rc car with a dance dance revolution pad via your pc, including source code. i call it “fitness racer”, because relative to coding, stepping on some buttons to drive an rc car is “fitness”.

surgical robot visualization (with intuitive surgical)

a real-time opengl visualization of intuitive's da vinci surgical robot system

killer death tag (with neel and soren)

robots playing tag... more accurately, robots running about while loud music plays and hopefully convinces the viewer that the robots are doing something useful. don't miss the exciting video. also check out neel's equally cynical and pseudo-profane take on the project.

virtual winter wonderland (with neel)

via “advanced computer vision techniques”, viewers are transported into a magical christmas world. and there are funny hats. part of the third-floor '03 holiday package.

la bastille (with techhouse)

...the greatest moment in the history of the pc's parallel port...

march of the snowmen (with the third-floor xmas team)

...was another entry in the Gates holiday decoration contest, including Spinny the spinning snowman and the musical light show.

alternative splicing in arabidopsis

When I was an intern at Cereon Genomics, I explored the frequency of alternative splicing in arabidopsis thaliana. Unfortunately, the work was proprietary, so I can't release the results. So I made this scientifically useless document describing my work without actually providing any information.

random scripts

i just created this directory to post random scripts that I've written and found to be useful in a way that may be useful to others. will populate more densely in the future.

dsm_datestamp

This is a useful little shell extension that I wrote to datestamp/timestamp files in Windows explorer (append time and date information to the filename), something I found myself doing manually a lot. For example, if I have a file called "hello.zip", I can right-click on it, select "dsm_datestamp", and it becomes "hello.05.04.13.1242.zip". Useful for project directories you often zip and archive, etc.

Installation instructions and source are included. Based on a nice tutorial on shell extensions by Michael Dunn.

multi_audio_lib

Windows make it easy to play sound files, but if you want to play a file simultaneously on multiple devices, or on a subset of available devices, or even on a non-default device, it can get a little tricky. This is a simple C++ library (with source) that lets you play any supported media type (e.g. mp3, wav) on any subset of available audio devices. In other words, it makes working with multiple formats and multiple audio devices as simple as the old standard "playsound" API.

The library is built in Visual C++ 2003 but should link fine in later versions; the 'lib' directory has the .h and .lib files that you care about.

You can also download the Java wrapper I wrote around an earlier version of the project, but I admit this project is not quite as clean as the C++ version. If you're using this library, there's a single .java file and a JNI .dll file that you care about.

stomp-a-grinch

I created Stomp-a-Grinch as part of the Computer Science building's annual Christmas decoration contest (here's a video of the robotics lab contest entry). It's a simple game that provides the simple satisfaction of stepping on things and hearing explosions. Basically various images appear that are either Grinches or friends-of-Christmas. You use a Dance-Dance-Revolution floor pad to stomp on the bad guys, and you rejoice. Here is some video of folks enjoying the Stomp-a-Grinch.

If you have a Playstation dance pad connected to your PC, you can play S-a-G too; download here (for win2k/XP). If you're curious about how one would make a game that makes use of a dance pad, you can download the source to s-a-g. Note that the source is a total mess, since this was written entirely in the 24-hour-period preceding the xmas contest. Should you find that you've actually downloaded this game and you want to make grinches blow up but you don't have a dance pad, you can use the TYU-GHJ-BNM grid on the keyboard to "stomp" on the nine squares in which items appear, and the 'S' key to start and stop the game.

handwriting synthesis

Confronted with the "Stanford Fund Problem", I wrote this set of Matlab scripts to allow automatic generation of text in my own handwriting. Basically you write some text, scan it, manually define a few examples of each letter (using a helpful GUI that the script provides), and feed it text. It randomizes which examples of each letter it uses, the exact position and spacing of the letters, the baseline of the text, the position of linebreaks, etc. I never have to write letters by hand again.

It should be noted that this package was never actually used for writing "Stanford Fund" letters, which - for those who have never experienced the agony that is TSF - are handwritten "thank you wealthy alumni" letters required of all student groups at Stanford who want money from the university. I'm sure it would work fine for that purpose, but I of course have never actually tried, because that would be a deep and insidious violation of tsf's trust, right?

Here is a tiny bit of example output. It looks crappy if IE shrinks the image (why did they start doing that?), so it will look more convincing if you make your browser wide enough so that it doesn't get resized.

palm keyboard driver

This is an application that allows you to use a Stowaway fold-up keyboard - intended for use with the Palm Pilot - with a PC. I could never find a connector for the Palm serial port output, so I ended up wrapping wires directly onto the keyboard; the wiring is described in the main .cpp file. This application was also ported to Linux shortly after I posted it to the wear-hard newsgroup on wearable computing.

I also wrote a 'calibration program' for this utility; I used it just to map scan codes from the Palm keyboard to Windows keyboard events. I run this, then pressed a key on the Palm keyboard, then the corresponding key on the 'real' keyboard, etc., and it generates the 'palmkey.ini' file that accompanies the above application. This program is _not_ very slick... there's just a console, no fancy icons, etc.

liblcd

This is a library that makes it convenient to write strings out to an Optrex-type LCD module - via the parallel port - from an application. It handles all the low-level interfacing, so your application can just print strings or characters. The optrex-type interface seems to be pretty standard; this is how most of the random character LCD's you come across are interfaced. I don't know whether this also applies to larger character LCD's, like the kind they use for highway signs. The wiring diagram is included, as is the manual for an optrex module that uses the standard interface. I also include the "portio" library - which I didn't write - that allows you to access arbitrary ports (specifically the parallel port i/o ports) in win2k/XP.

speechtest_win

This is a fun application that demonstrates the Microsoft speech API, as it can be used to do something useful in very few lines of code. In this case, I use the "useful strings" library (described below) to get fun strings from the web (like news headlines, etc.) and I use the MS Speech API to read them out loud. If you ever wanted to make your code talk, MS makes it as easy as printf... Basically this application pops up a little dialog box that asks the user what he/she wants to hear (MSNBC, The Onion, the time of day, some random text file in my web directory, etc.) and how often the information should be read aloud. You'll need to install the MS speech SDK, which is free, to play with this app...

parport_controller

This is a fun application that I wrote when I was prototyping a controller by wiring all the buttons up to the parallel port (the parallel port actually is a pretty good way of prototyping a lot of simple interfaces). The application pops up a dialog box with one page for each of the eight bits on the parallel port; the user selects an item that specifies what should happen when that bit changes state (with separate repsonses to on and off). The events I've defined include generating mouse events, launching applications, etc. But the structure of the program hopefully makes it easy to add new events.

J.O.H.N.

Java-based observation of the Hopfield Network, a project I did for a neural networks class I took as an undergrad. Basically this is here because I'm _still_ amused with the fact that Java can really run in a web browser.

usefulstrings.zip

This is a library that provides a variety of "useful strings" for an application that needs fun strings to play with (the next couple zipfiles are examples). It has a couple of strings that are available locally (like the time of day, etc.), but it's mostly code that goes out to web sites like msnbc, the onion, etc. and parses their headlines out.

lcd_news.zip

This project behaves just like the "speechtest_win" project describe above, but instead of reading the strings aloud, it prints them out to an LCD module on the parallel port, using the above "liblcd". This is a rare example of something potentially useful that you might want to do with a character LCD module...

linear elastic material properties

"linear elastic material properties" is a little tutorial i put together to remind myself what the basic elastic moduli mean, since they come up just often enough in my life that I need to remember what they are but just infrequently enough that i never remember which is the bulk modulus and which is the young's modulus, etc.

the inertia tensor

"what the hell is the inertia tensor?" is a little tutorial i put together to remind myself of the intuition i achieved at some point regarding a topic that comes up a lot in graphics, haptics, robotics, and simulation.

transistors as switches

often times i find myself needing a simple transistor circuit for a hobby project, and - being not at cosmic oneness with the n or the p - i typically forget how to connect them, which is the base and which is the emitter, etc. "using transistors as switches" is a little tutorial i put together so i could just download what i usually forget on this topic whenever it comes up.

an intuitive but not-all-that-mathematically-sound explanation of the fourier transform

"an intuitive but not-all-that-mathematically-sound explanation of the fourier transform" is a little tutorial i put together to walk non-signal-processing folks through the typical formulation of the fourier transform, somewhere between an explanation and a pneumonic device. this way of looking at it really helped me in my first signal processing course; hopefully it will be helpful to someone else too...

physical simulation paper summaries

I've summarized a few recent papers that I've found to be particularly helpful in getting up to speed on physical simulation and related topics. Excellent papers one and all.

Large Steps in Cloth Simulation (Baraff and Witkin) [summary]

Accurate Real-Time Deformable Objects (James and Pai) [summary]

Precomputing Interactive Dynamic Deformable Scenes (James and Fatahalian) [summary]

EigenSkin (Kry, James, and Pai) [summary]

Deformation Transfer for Triangle Meshes (Sumner and Popovic) [summary]

Modeling by Example (Funkhouser et al) [summary]

Fluid Control Using the Adjoint Method (McNamara et al) [summary]

A Versatile and Robust Model for Geometrically Complex Deformable Solids (Teschner et al) [summary]

Stable Fluids (Stam) [summary]