brainwagon

Okay, simulating the analog parts of the actual physical ring oscillator last night made me ask some questions, so I thought it might be useful to try a very simple discrete simulation. If you looked at the schematic I posted yesterday, you’ll note that the ring is really just made up of single transistor inverters. […]

I tweeted this earlier, but in case you aren’t subscribed to my twitter feed (user brainwagon) then you should check it out: some Google engineers sent one of their mascots to over 100K feet altitude along with several Android phones to record the experience. The video is awesome. Android In Spaaaace! – Official Google Mobile […]

Every once in a while, I feel like making high quality pictures of ground tracks of satellites. The Generic Mapping Toolkit is handy, especially when combined with the pyephem library. The thick line is the ground track of the amateur satellite AO-51, at any point in its next pass where it is visible from my […]

Lost in yesterday’s thrilling launch of the SpaceX Falcon-9/Dragon launch was that during their flight, they also apparently deployed a cubesat: CAERUS (which is apparently Greek for “opportunity”). It has a 900mw FM AFSK beacon downlink on 437.600, and operates under the amateur callsign KJ6FIX. I have not as yet been able to locate TLEs […]

A couple of months ago, I did some simple simulations of light refracting through raindrops in a hope to understand the details of precisely how rainbows form. The graphs I produced were kind of boring, but they did illustrate a few interesting features of rainbows: namely, the double rainbow, and the formation of Alexander’s band, […]

Luke Gesissbuhler did a balloon launch, lofting an HD video camera and an Apple iPhone to lofty heights before recovering them. Very nice. The footage right after burst was kind of cool: I was wondering whether the fragments of the balloon or parachute tangled with the camera: perhaps dangling the camera on a longer tether […]

A few years ago I spent a couple of hours tinkering with implementing Thad Walker’s scheme for printing computer generated holograms (see the link for the paper): Printing Holograms on a Laser Printer A recent comment has got me thinking that I should revisit the idea and the paper. For reasons which aren’t entirely clear […]

Nyle Steiner gets a link from me again, this time for his construction of T.E.A. lasers. I remember reading about these kind of lasers in an issue of Scientific American (I just looked it up, Jun, 1974 in the Amateur Scientist column), but that was the extent of it. Nyle has done a lot of […]

I was hoping to find a copy of René Descartes treatment of rainbows as part of Project Gutenberg (hopefully in English) but no dice. It does appear that the Université de Québec has the work Les Météores as part of their online collection. It’s far too late for me to work on reading it (my […]

A few days back, I simulated how light propagated in a single drop of water, but with a number of problems. First of all, it didn’t simulate the Fresnel equations, which describe how light is reflected and refracted at the interface between two media. This meant that in my simple model, no light is actually […]

I’ve seen the Khan Academy listed a couple of times before, but never really bothered to look at it again until today. I was confused about a minor issue in linear algebra (hey, it’s been 25 years since I took linear algebra) so I surfed over and found the lecture on null subspaces to be […]

On hack-a-day today, I saw this interesting link to a small hydroelectric generator. I’ve been interested in DIY/non-centralized generation of electricity for quite a while (without actually developing any serious knowledge about it, mind you) so I found the idea rather interesting. Paul taps water from a stream and uses it to feed a 2 […]

A couple of days ago, I linked to an article which talked about using a laser beam as a kind of microscopic projector. The collimated laser light passes into a small drop of water, and then casts the image of protozoa (or other small swimmers) onto the wall. Very cool, but I wasn’t entirely sure […]

An interesting impromptu project: a laser pointer directed through a drop of water projects a large magnified image on the wall. Teravolt.org – Laser Microscope. This reminded me of the setup that Gabor described decades ago for inline digital holography. I might have to give this a try sometime. httpv://www.youtube.com/watch?v=2aK_a-jr-tI

I might have an opportunity in a couple of weeks to go do some kite flying at an upcoming picnic, and I thought that I might give a quick try at quick and dirty kite photography. After all, I’ve been musing about lofting a camera up high using a weather balloon, so why not start […]