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

Self-hosting Mail – Hurdles

Jan 20, 2016

My troubles with self hosting a mail server. In the name of countering spam, mail has become such a quagmire of blacklisting, whitelisting, etc. – in other words – censorship. email is in danger of becoming gmail. email is such an elegant set of protocols with decentralization built into its heart. We must not let it become a victim to centralization.

Tags: selfhosting, internet

What is Free Software?

Jan 18, 2016

This is a republication of an introductory article I wrote for the Issues of Concern , a newsletter run by Concern, a left leaning students' political organization in the Indian Institute of Science, Bengaluru. The article is mostly a paraphrase of the philosophy pages of the GNU project in an attempt to explain what free software is to the average Issues of Concern reader. Many thanks are due to Raghunath Joshi for editing and improving the article.

Tags: freesoftware

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

Quiz Buzzer v2

Nov 20, 2014

After being stuck in development hell for a few years now, version 2 of the Quiz Buzzer is at last here. The final iteration of polishing/testing/reengineering has been done, and the buzzer is finally complete. The new buzzer is one single all in one board with the LED seven segment display, the display driver circuitry and the controller circuitry all integrated into one monolithic PCB. Finally, from prototype to usable product…

Tags: electronics, project

Cylone Hudhud - APT Images

Oct 16, 2014

An APT image of Cyclone Hudhud I received on October 11 in Bangalore…

Tags: radio, satellite, rtlsdr, sdr, weather

The Quadrifilar Helix and APT Yet Again!

Jul 06, 2014

Manjunath and I have been meaning to do something these hols - you know, just something to feel a sense of satisfaction before diving into regular coursework and stuff next semester. So, we finally decided to attempt a quadrifilar helix for APT reception, and here we are!

Tags: radio, satellite, rtlsdr, sdr, weather, antenna, project

Walk to Sankey Tank

Jun 01, 2014

Just a pleasant Sunday morning's walk to Sankey tank with Tarun and Vaibhav…

Tags: walk

IISc Mess Subsidy Protests

Apr 11, 2014

On Thursday, April 10, the students of IISc protested the administration's proposal to cancel the mess subsidy. I myself participated and was witness to the proceedings. Here is a short account of the events of the day and a comparison of various newspaper reports on the incident.

Tags: iisc, musing

APT Again!

Jul 31, 2013

It is quite possible for someone to ask why, in the age of the Internet and the Television, and realtime weather reports, we need APT images. But, you will never know the joy of building your own equipment, and receiving your very own satellite images, until you have actually done it!

Tags: radio, satellite, rtlsdr, sdr, weather

Like Frogs in a Well

May 23, 2013

Simple visualizations (such as the one shown in the figure) of this curvature, typically appeal to a 2D fabric of space curved into a third dimension by the presence of a mass such as the earth. This curvature creates a three dimensional "well" into which other masses fall, thus resulting in what we perceive as gravity.

Tags: musing, physics