Checking Out Mount Olympus From 38 Km

September 14, 2012 by Brian Benchoff 6 Comments

The image above shows Mount Olympus in the center, with a tiny bit of the western suburbs of Thessaloniki, the second largest city in Greece, in the lower right hand corner. These two points are 70 kilometers apart, but we’re not seeing a picture taken from the International Space Station. This is a picture from the SlaRos project, a high altitude balloon launched last summer that ascended to 38 kilometers above Greece.

On SlaRos’ project page (Facebook warning), the team covers the hardware that went in to lofting a camera high above the cruising altitude of commercial airplanes. A GPS module tracked the balloon in real time and relayed this to a GSM module to the mobile command and tracking team.

There are a ton of high altitude pictures of Greece over on the project’s Facebook page as well as a time lapse video of the Grecian wilderness after the SlaRos payload landed. The payload spent a full night in a field before it was recovered, but we’re very glad the team was able to recover these awesome pictures.

Radio Built From The London Underground Map

September 13, 2012 by Mike Szczys 20 Comments

We love it when PCB artwork is actually artwork. Here’s one example of a radio whose layout mimics the map of London’s subway system.

The build is for an exhibit at the London Design Museum. They have an artist in residence program which allowed Yuri Suzuki time and resources to undertake the project. He speaks briefly about the concepts behind it in the video after the break.

The top layer of copper, and silk screen was positioned to mirror the subway lines and stops on a traditional transportation map. Major components represent various transfer hubs. In this way he hopes the functioning of the circuit can be followed by a layman in the same way one would plan a trip across town.

This may be a bit more abstract than you’re willing to go with your own projects. But there are certainly other options to spicing you track layout.

Continue reading “Radio Built From The London Underground Map” →

Displaying Images On The Surface Of Bubbles

September 3, 2012 by Brian Benchoff 13 Comments

The image you see above isn’t a simple photograph of our blue marble from thousands of miles above. No, that image is much cooler than a satellite because it’s a projection of the Earth onto a soap film screen. Yes, we can now display images on the surface of bubbles.

Instead of a the soap bubbles you’d normally give a small child, this project uses a mixture of sugar, glycerin, soap, surfactant, water, and milk to produce a film much more resistant to popping than your standard soap bubble. Shining an image through these films doesn’t result in much of an image, so the researchers used ultrasonic speakers to vibrate the film and make it possible to display a picture.

With a small projector, this system makes it possible to display an image on the surface of bubble. Of course, the display area is tiny right now, but the size will most likely increase as the experimentations continue.

You can check out a whole bunch of videos demoing this tech after the break.

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Doubling Down On Motor Drivers

August 30, 2012 by Mike Szczys 31 Comments

Motor driver chip too weak for your needs? Just use two of them. That’s the advice which [Starlino] gives. He stacks motor driver chips to product move powerful controllers.

When stacked as shown, the driver combos should be able to drive at 4A. This is partly because he ganged together the outputs in pairs, and also because of the stacking. That’s a lot of juice, but [Starlino] documented his testing stage which shows that they’re up to it. It’s a bit hard to see from this angle, but he is using a serpentine heat sink. It snakes its way between the stack of chips, then over the top chip before folding back and spreading its wings. The motors he’s using have a stall current of 3.7A, and he included resettable fuses graded at a 2A hold current. He’ll be glad to have that extra protection is something goes wrong with the drivers.

[Thanks Roger]

Gilded Hello Kitty Ax Made Using Electrolysis

August 29, 2012 by Mike Szczys 36 Comments

Ummm…. cute? For the Hello Kitty fan who has everything?

Yeah, we’re really not sure what’s going on here. It’s an art piece on which [Denis] spent a lot of time. He polished it, etched it, painted it, applied gold leaf, and drilled a hole for a charm. It’s that hole which interested us the most. He had a heck of a time figuring out how to make a hole in the hardened steel. The solution that finally worked was to use electrolysis to bore through the metal (translated).

[Denis] first made a small depression where he wanted the hole. This took time, and pretty much ate through the engraver bit he was using. But it was just enough to hold a drop of saline. He connected the positive side of his power supply to the ax head, then dipped the negative lead into the drop of saline. Each time the drop turned black he wiped it away and replaced it with fresh solution. Just five hours of this and a pack or two of cotton swabs and he was through.

Build Your Own Forge Inside A Gallon Paint Can

August 27, 2012 by Mike Szczys 14 Comments

If you’d like to try your hand with the art of Blacksmithing but don’t want to go all-in on your first project this may be for you. It’s a forge which you can build for under $100. [Mike O’s] creation has some great features, like the option of using the forge as a pass through, and he finds it’s possible to heat metal up to 4″ wide.

He bought an empty paint can at the home store (we guess you don’t want fumes from any paint residue). The business end of the forge is actually the bottom of the paint can. He cut a small opening, then lined the inside of the can with Insulwool, a fabric used as heat shielding. From there the inside was lined with several layers of Satanite Refractory Cement. The same applications were made to the paint can’s original lid, which serves as the back of the forge. This way it can be removed for that pass-through we mentioned earlier.

A propane torch brings the heat for this project. [Mike] mentions that you’re going to want to do the first few firings outside as the cement really stinks until it’s been through a few heating cycles. This creation should get him started but we bet he’ll upgrade to something like this coal forge before long.

[via Reddit]

Measuring The Speed Of Sound With Science And Statistics

August 27, 2012 by Brian Benchoff 22 Comments

Despite what you may have heard elsewhere, science isn’t just reading [Neil deGrasse Tyson]’s Twitter account or an epistemology predicated on the non-existence of god. No, science requires much more work watching Cosmos, as evidenced by [Ast]’s adventures in analyzing data to measure the speed of sound with a microcontroller.

After [Ast] built a time to digital converter – basically an oversized stopwatch with microsecond resolution – he needed a project to show off what his TDC could do. The speed of sound seemed like a reasonable thing to measure, so [Ast] connected a pair of microphones and amplifiers to his gigantic stopwatch. After separating the microphones by a measured distance; [Ast] clapped his hands, recorded the time of flight for the sound between the two microphones, and repeated the test.

When the testing was finished, [Ast] had a set of data that recorded the time it took the sound of a hand clap to travel between each microphone. A simple linear regression (with some unit conversions), showed the speed of sound to be 345 +/- 25 meters per second, a 7% margin of error.

A 7% margin of error isn’t great, so [Ast] decided to bring out Numpy to analyze the data. In the first analysis, each data point was treated with equal weight, meaning an outlier in the data will create huge errors. By calculating the standard deviation of each distance measurement the error is reduced and the speed of sound becomes 331 +/- 14 m/s.

This result was better, but there were still a few extraneous data points. [Ast] chalked these up to echos and room vibrations and after careful consideration, threw these data points out. The final result? 343 +/- 9 meters per second, or an error of 2.6%.

A lot of work for something you can just look up on Wikipedia? Yeah, but that’s not science, is it?