Announcing exiftool.el

Mar 02, 2017

This is to announce the release of exiftool.el, an emacs lisp wrapper around ExifTool. ExifTool is a command line application supporting reading and writing metadata in various formats including EXIF, XMP and IPTC.

Tags: software, project, freesoftware

Black body energy as a sum of photon oscillator energies

Nov 01, 2016

This is a graph I made for contributing to Wikipedia. It shows the energy of a black body as the sum of energies from oscillators with 1 photon, 2 photons, 3 photons, etc.

Tags: physics, gnuplot, software

User script to remove noscript mask on ebay

Aug 30, 2016

A greasemonkey user script that removes the noscript mask on ebay and lets the user browse ebay without enabling javascript…

Tags: javascript, software, greasemonkey

Elegant bash one liner to generate passphrase

Jul 27, 2016

An elegant bash one liner to generate a passphrase – shuf from coreutils is the secret ingredient.

Tags: software, bash

A simple passphrase generator in bash

Jul 20, 2016

Yet another passphrase generator, this time one in bash…

Tags: project, software, bash

NASA Astronomy Picture of the Day bot for GNU Social

Jun 11, 2016

A bash script, run periodically by a cron job, to post the day's NASA Astronomy Picture of the Day to GNU Social. The script uses GNU Social's Twitter compatible API to publish notices.

Tags: gnusocial, astronomy, project, software, bash

fold and stream-fold pass arguments to proc in different orders

Mar 24, 2016

SRFI-1 fold and SRFI-41 stream-fold pass arguments to proc in different orders. Violating the principle of least astonishment, this comes as a rather inconvenient surprise to the programmer.

Tags: lisp, scheme, functionalprogramming, software

Fourier Reconstruction of an Image

Dec 11, 2014

Any image can be reconstructed using just a superposition of plane waves of different spatial frequencies. This is a numerical experiment using a NumPy script that reconstructs an image one frequency component at a time.

Tags: math, signals, software

Line Codes - Matlab / GNU Octave Code

Jul 19, 2012

I came up with the following approach to do line coding without for loops. My approach involves a bit of system theory, modulo 2 arithmetic, and sometimes just tricks founded on simple coincidence. So one is advised to be a little careful while sifting through the logic. But ultimately, the code is terse and fairly elegant.

Tags: signals, matlab, octave, software

Stochastic Simulation

Mar 17, 2012

This is a loose collection of programs we wrote as part of a course on "Stochastic Models" we had in the fourth semester of college. This includes a couple of pseudo random number generators (the Von Neumann middle square PRNG and the linear congruential generator PRNG), an implementation of the Monte Carlo method to determine area of an arbitrarily shaped figure and a simple simulation of birth-death process.

Tags: c, tcl, gnuplot, project, software

Resistor Color Codes Script

Mar 17, 2012

I just decided to write a Python script to convert resistor color codes to resistance values. Later, I also wrote a script to do the reverse - namely to find the color code of a given resistor.

Tags: electronics, python, software, project

Signal Operations Applet

Mar 17, 2012

This is actually a set of two "applets" we did as part of an assignment for "Signals and Systems" in the fourth semester of college. The goal was to write an application which illustrated basic signal operations such as shifting, scaling, folding and also signal addition and multiplication. This series regulated power supply provides an output voltage of about 5.3 V and a maximum current of almost 500 mA. As can be seen from the VI curve of the power supply, the quality of regulation isn't awesome. Still, I guess, acceptable for a first attempt…

Tags: signals, software