systemreboot – blog

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 6, 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 1, 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

Over the Arabian Sea

Feb 26, 2013

…here at last, we have these spectacular images - images that rained down from the sky! It's true that they are still imperfect, and rather noisy (a situation that I intend to fix soon). But, anyway, here they be recorded, before the miracle of the moment passes away…

Tags: radio, satellite, weather, electronics, project

RC Phase Shift Oscillator - Oscillation Criteria

Jan 20, 2013

Maxima is a computer algebra system. That's kinda like a calculator that can do algebra instead of just numerical calculations! I let Maxima cut through all the algebra of the RC phase shift network. Lo and behold, here we have the results, achieved almost painlessly!

Tags: electronics, maxima

CyanogenMod 9 on my HTC Explorer!

Jan 8, 2013

I often hear all this talk about how the Explorer is a "low end budget device", about how 600 MHz is just too slow, and so on. But frankly, I can only classify all this as sales talk, or perhaps uninformed talk. Ice Cream Sandwich is not in any way slow on the Explorer, all hardware works fine, and I would certainly recommend anyone with an Explorer flashing to CyanogenMod 9.

Tags: android, cyanogenmod

Frogs, Humans and the Radio

Oct 1, 2012

…in effect, SSB radio is like shouting above the din of the noise existing in the band. The noise always exists in the band, and in order to be heard, one must shout above the noise.

Tags: musing, radio

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