Shared State

With some help from the R2 Builders Club, my wife and I built an R2-D2! He drives, makes sounds, and lights up, but there's still a lot to do. For example, we haven't hooked up all the motors inside the dome and the motor to make the dome spin.

Here's …

Copying a Time Machine backup from one disk to another is difficult. The official instructions say to copy using Finder. While this may work for a small time machine backup, it does not work well if you have been using time machine for several computers for several years. In particular …

I spent an embarassing amount of time on this, so I thought I would document it.

brew install postgresql unixodbc psqlodbc

Start up postgres:

postgres -D /usr/local/var/postgres

Check that you can connect to the database:

psql

Inside postgres, create a user with a password. You probably need …

First you will need to know the name of the node:

select * from nodes;

Then mark it as ephemeral:

alter node v_demo_node0001 is ephemeral;

I've wanted to try a Vim Clutch for a few years now, but once I got it set up, it turned out to be disapointing.

A Vim Clutch is a foot pedal that toggles between insert mode and normal mode. I set my clutch up a bit differently than the …

I think it would be cool to find local crowds of people discussing a topic online. What are people in Brazos county saying about Obama? Who in my town is having interesting philosophical discussions? What are people in Austin saying about Starbucks?

While working towards that goal, I did my …

Imagine you're building a web app in Django, and you want the user to enter a number between 1 and 100 on a web form. Where do you put the code to check that the number is between 1 and 100? If you want a slick user interface, you have …

Lately, I've been looking into using Javascript for both client and server-side web development. Starting a project in Node.js today feels a lot like reading a Choose-Your-Own-Adventure book—every few minutes you have to choose between a few options, and it's not obvious which one is the optimal. Javascript …

Requests is a great library for making HTTP requests. We're using it quite a bit in Infolab to talk to Twitter. Right before they released version 1.0, Requests made a slight change to its streaming API, so the old code results in this error message:

Traceback (most recent call …

Programmers often read through code one function at a time or trace through a program following the path of execution. Today, I'm going to look at a program in a different way: I'm going to look at how one line changed over time. The line I'm going to look at …

FriendlyLocation is a system for predicting the location of users on Twitter. It was the topic of my masters thesis, and I am currently converting the thesis into a paper for publication.

VineMap is a quick project I did a few days after Vine launched. I use Twitter's streaming API to listen for links to Vines. I then geocode the location field from the Twitter's user profile. (I'm throwing away vines posted by users without understandable locations.) I put the tweets in …

Ipython's PyLab breaks some uses of any(), all(), and possibly other built-in functions. Here's a normal IPython shell:

>ipython
In [1]: all([x for x in [0,1,2]])
Out[1]: False

In [2]: all(x for x in [0,1,2])
Out[2]: False

In [3]: all
Out[3 …

I was the TA for Texas A&M's Information Retrieval class in 2012. We took some interesting directions with the homework assignments, so I'd like to spend some time talking about the experience for the benefit of other educators. The professor, Dr. Caverlee wanted to change the existing set of …

If you use sudo su to become a different user, and then try to create a screen session for the new user, it gives this error message:

Cannot open your terminal '/dev/pts/1' - please check.

The problem is that your original user still owns the pseudo terminal. The best …

Pdb is Python's built-in debugger. To make it easier to start pdb, I added this line to my .vimrc:

noremap <D-d> Oimport pdb; pdb.set_trace()<Esc>:w<Return>

When I type Command-d in normal mode, vim will insert the line import pdb; pdb.set_trace() and save the current file …

GWJeroo is a library that lets students run Jeroo programs in GridWorld. GWJeroo is intended for students in Pre-AP and AP classes who are transitioning from Jeroo to Java.

I developed this in 2007 when I was a high school computer science teacher. I no longer teach, so I don't …

Fitz is a window decoration for KDE that allows you to work (or play) faster.

Unlike other decorations, Fitz does not have a titlebar above the window; instead, it puts the buttons on the top right corner of the window in the menubar. As a result, when a window is …

Ingredients

3 chicken breasts 3 slices fried bacon 1 cup whipping cream 1⁄4 cup tabasco chipotle sauce 3 bananas 1 T cummin 1⁄2 cup peanuts 1 cup cooked rice

Instructions

1. Marinate the chicken breasts in Tabasco Chipotle sauce and grill them. Fry bacon and break it into bits …