Cascade LNAs and Filters for Radioastronomy with an SDR

It may not be the radio station with all the hits and the best afternoon drive show, but 1420.4058 MHz is the most popular frequency in the universe. That’s the electromagnetic spectral line of hydrogen, and it’s the always on the air. But studying the H-line is a non-trivial task unless you know how to cascade low-noise amplifiers and filters to use an SDR for radio astronomy.

Because the universe is mostly made of hydrogen, H-line emissions are abundant, and their distribution can tell us a lot about the structure of galaxies. The 21-cm emission line is so characteristic and so prevalent that we used it as a unit of measurement on the plaques aboard the Pioneer probes as well as in the instructions for playing back the Voyager recordings. But listening in on 21-cm here on Earth requires a special setup, which [Adam (9A4QV)] describes in a detailed paper on the subject (PDF). [Adam] analyzes multiple configurations of LNAs and filters, both of which he sells, to determine the optimum front-end for 21-cm work. His analysis is a good primer on LNAs and explains why the front-end gear needs to be as close to the antenna as possible. Using his LNAs and filters and an SDR dongle, a reasonable 21-cm rig can be had for about $200 or so, less the antenna. He promises a follow-up paper on homebrew 21-cm antennas; we’ll be looking forward to that.

Not keen on the music of the spheres and prefer to listen to our own spacecraft instead? Then read up on the Deep Space Network and how you can snoop in.

Coke Can Fueled Power Generator

[Experimental Fun] shows us how you can create a cola power generator that runs on nothing more than cans of cola including the container and a little bit of sodium hydroxide to speed the reaction up.

This might sound a bit crazy, but it seems you can power an engine on little more than your favorite fizzy drink and the cut-up remains of an aluminum can. What happens is that aluminum and water create a chemical reaction when mixed together, which gives off hydrogen. Normally this reaction is very slow and would take years to make any noticeable marking on the aluminum, but with a little help from sodium hydroxide the reaction is sped up to such a rate that hydrogen is produced quite quickly.

The crazy contraption they created has a reaction chamber which then feeds the hydrogen through condenser then to a bubble filter made from a bottle filled with water. After that it is on through a carbon filter to get rid of any impurities, and finally it is fed directly into a two-stroke engine’s fuel line. Then engine still needs an electric start from a battery, but after that it runs directly on the hydrogen created during the reaction from the chamber.

This is quite a cool project, however you could replace the fizzy drink with water and still get the desired effect. Since the drink comes with the aluminum cans it seems like quite a good fuel though. There are other crazy fuels out the for the avid DIY hacker, but just be careful and don’t blow yourself up.

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Experimental Gases, Danger, and The Rock-afire Explosion

DowntownExlosion12_1On the morning of September 26th, 2013 the city of Orlando was rocked by an explosion. Buildings shook, windows rattled, and Amtrak service on a nearby track was halted. TV stations broke in with special reports. The dispatched helicopters didn’t find fire and brimstone, but they did find a building with one wall blown out. The building was located at 47 West Jefferson Street. For most this was just another news day, but a few die-hard fans recognized the building as Creative Engineering, home to a different kind of explosion: The Rock-afire Explosion.

The Inventor and His Band of Robots

rockafireMany of us have heard of the Rock-afire Explosion, the animatronic band which graced the stage of ShowBiz pizza from 1980 through 1990. For those not in the know, the band was created by the inventor of Whac-A-Mole, [Aaron Fechter], engineer, entrepreneur and owner of Creative Engineering. When ShowBiz pizza sold to Chuck E. Cheese, the Rock-afire Explosion characters were replaced with Chuck E. and friends. Creative Engineering lost its biggest customer. Once over 300 employees, the company was again reduced to just [Aaron]. He owned the building which housed the company, a 38,000 square foot shop and warehouse. Rather than sell the shop and remaining hardware, [Aaron] kept working there alone. Most of the building remained as it had in the 1980’s. Tools placed down by artisans on their last day of work remained, slowly gathering dust.

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Hackaday Prize Semifinalist: A Low Cost, DIY Fuel Cell

Electronic cars and planes are the wave of the future, or so we’re told, but if you do the math on power densities, the future looks bleak. Outside of nuclear power, you can’t beat the power density of liquid hydrocarbons, and batteries are terrible stores of energy. How then do we tap the potential of high density fuels while still being environmentally friendly? With [Lloyd]’s project for The Hackaday Prize, a low cost hydrogen fuel cell.

Traditionally, fuel cells have required expensive platinum electrodes to turn hydrogen and oxygen into steam and electricity. Recent advances in nanotechnology mean these electrodes may be able to be produced at a very low cost.

For his experiments, [Lloyd] is using sulfonated para-aramids – Kevlar cloth, really – for the proton carrier of the fuel cell. The active layer is made from asphaltenes, a waste product from tar sand extraction. Unlike platinum, the materials that go into this fuel cell are relatively inexpensive.

[Lloyd]’s fuel cell can fit in the palm of his hand, and is predicted to output 20A at 18V. That’s doesn’t include the tanks for supplying hydrogen or any of the other system ephemera, but it is an incredible amount of energy in a small package.

You can check out [Lloyd]’s video for the Hackaday Prize below.

The 2015 Hackaday Prize is sponsored by:

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Retrotechtacular: Using the Jet Stream for Aerial Warfare

Unmanned Aerial Vehicles (UAV) are all the rage these days. But while today’s combative UAV technology is as modern as possible, the idea itself is not a new one. Austria floated bomb-laden balloons at Venice in the middle 1800s. About a hundred years later during WWII, the Japanese used their new-found knowledge of the jet stream to send balloons to the US and Canada.

Each balloon took about four days to reach the western coast of North America. They carried both incendiary and anti-personnel devices as a payload, and included a self-destruct. On the “business end” of the balloons was the battery, the demolition block, and a box containing four aneroid barometers to monitor altitude. In order to keep the balloons within the 8,000 ft. vertical range of the jet stream, they were designed to drop ballast sandbags beginning one day into flight using a system of blow plugs and fuses. In theory, the balloon has made it to North American air space on day four with nothing left hanging but the incendiaries and the central anti-personnel payload.

Although the program was short-lived, the Japanese launched some 9,300 of these fire balloons between November 1944 and April 1945. Several of them didn’t make it to land. Others were shot down or landed in remote areas. Several made the journey just fine, and two even floated all the way to Michigan. Not bad for a rice paper gas bag.

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The Platinum Catalyst Use in a Vintage Lighter

[Ben Krasnow] has an inimitable knack for choosing the most interesting concepts for his experiments. We’re sure it’s a combination of base knowledge and epic-curiosity. This time around he’s showing off a vintage cigarette lighter whose quirk is not needing to be “struck” to produce a flame. It’s a catalytic lighter that uses platinum to ignite methanol vapors.

The concept shown in the video below is platinum’s catalyst properties with some types of flammable gasses. The image above shows the cap of the lighter which includes a protective cage around a hunk of fine platinum powder known as platinum black. It is suspended by platinum wire and as the hydrogen passes by the reaction causes the platinum black and wire to glow red-hot.

This simple, quick experiment fills in our own knowledge gaps. We were already familiar with the role that catalytic converters play in automobiles; consuming any unburned hydrocarbons before they exit a vehicle’s exhaust system. We also know the these devices are targets for thieves seeking the platinum (and other metals like palladium and rhodium) found inside. Now we know exactly how catalytic converters work and the integral role that platinum plays in the process. All thanks to [Ben’s] demonstration of how this lighter works.

Now, if you wear a platinum wedding band and your hand passes a jet of hydrogen are you likely to get burned?

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Powering a RPi with Hydrogen

raspberryHy

Looking for a new way to power your Raspberry Pi? The raspberryHy project aims to develop a small fuel cell designed for powering the credit card sized computer. It adds a proton exchange membrane (PEM) fuel cell, a battery, and custom control electronics to the Pi.

The system takes hydrogen in from a compressed hydrogen cartridge and feeds it through a regulator. This passes the hydrogen into the PEM fuel cell at the correct pressure, and creates a potential. The control electronics boost that voltage up to the 5 V required on the Pi’s USB port. There’s also an electronically controlled purge valve which periodically exhausts the fuel cell.

There’s a few reasons you might want to run your Pi with hydrogen. Run time of the fuel cell is limited only by the amount of hydrogen you can store. In theory, you could connect a large cylinder for very long run times. Combined with a battery, this could be quite useful for running Pis in remote locations, or for long-term backup power. The raspberryHy will be presented at Hannover Fair 2014 this month.