Category Archives: Programming

Kaoss Guitar – Day 1

Posted on 2010-04-18 by David

For a while, a friend and I have been planning to build a specialized MIDI controller into a guitar to control a Korg Kaoss Pad KP2. The idea came from the guitar used by Matt Bellamy of Muse (check out … Continue reading →

Posted in Electronics, Linux, Programming | Leave a comment

Using Cairo in Pygame

Posted on 2010-03-29 by David

This is a method of using Cairo with Pygame. It works by sharing the same block of memory for the Cairo drawing surface and the Pygame image surface. The only trick to it is making sure that Cairo and Pygame … Continue reading →

Posted in Programming | Leave a comment

SparkFun’s FTDI Basic Breakout as an AVR programmer

Posted on 2009-12-20 by David

Start by following my instructions for setting up AVRDUDE 5.8 with FTDI bitbanging support. Now open up avrdude.conf in a text editor. Add this entry by the other programmers: # FTDI basic breakout programmer id = “ftdi”; desc = “FTDI … Continue reading →

Posted in Electronics, Programming | 4 Comments

AVRDUDE 5.8 with FTDI bitbang patch on Linux

Posted on 2009-12-20 by David

Description: This is an adaptation of the work by Kimio Kosaka, Nate Phillips, and Massimo. It allows you to use AVRDUDE with an FTDI chip (like the one on the Arduino boards or SparkFun’s FTDI Basic Breakout). This can be … Continue reading →

Posted in Electronics, Programming | 14 Comments

Accessing AVR GPIOs via bit fields

Posted on 2009-12-08 by David

I noticed that the TMS320F2809 examples accessed GPIOs by bits rather than as 32-bit ints. For example, it’s possible to set a GPIO like this on the TMS320F280x: GpioDataRegs.GPADAT.bit.GPIO12 = 1; // Sets GPIO12 to high. Normally when working with … Continue reading →

Posted in Electronics, Programming | Leave a comment

RK4 in Haskell

Posted on 2009-07-31 by David

Ran across this today. It’s a well written implementation of RK4. 4th order Runge-Kutta (RK4) integration in Haskell

Posted in Mathematics, Programming | Leave a comment

Line Segment to Circle Collision/Intersection Detection

Posted on 2009-07-13 by David

Style and Notation All variables are represented in italics except in the diagrams and Python code. Vectors are shown in bold except in the diagrams and Python code. The notation |a| is used to represent the length of a vector … Continue reading →

Posted in Computational Geometry, Mathematics, Physics, Programming | 6 Comments

JavaScript Image Animation

Posted on 2009-06-24 by David

I made a small script to produce an animation with a series of images and JavaScript. I only tested it in Firefox 3, but I don’t see any reason why it wouldn’t work in other browsers. Try it: http://doswa.com/projects/animate/ Download … Continue reading →

Posted in Programming | Leave a comment

PHPNotify: Debug Notifications From PHP

Posted on 2009-05-13 by David

This is a little program to help debug AJAX (or anything else) from PHP. Read the README file to instructions on setting it up on Ubuntu. Note that you must first install python-notify through apt-get for this to work correctly. … Continue reading →

Posted in Programming | Leave a comment

Improved RK4 Implementation

Posted on 2009-04-21 by David

This is a Python implementation of the RK4 numerical integrator that works with differential functions of all orders. That is, any function in the form F(x, y, y’, y”, …, ). If you’re new to numerical integration or even RK4 … Continue reading →

Posted in Mathematics, Physics, Programming | Leave a comment