20 pounds and a gut feeling yields a configurable Rubidium atomic clock source

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So you see an image like this and the description “Aircraft stable oscillator” on an eBay listing for twenty pounds (about thirty bucks), what do you do? If you’re [Alecjw] you buy the thing and crack it open to find an atomic clock source inside. But he really went the distance with this one and figured out how to reconfigure the source from the way it was set up in the factory.

First off, the fact that it’s made for the aerospace industry means that the craftsmanship on it is simply fantastic. The enclosure is machined aluminum and all of the components are glued or otherwise attached to the boards to help them stand up to the high-vibrations often experienced on a plane. After quite a bit of disassembly [Alec] gets down to a black box which is labeled “Rubidium Frequency Standard”… jackpot! He had been hoping for a 10 MHz signal to use with his test equipment but when he hooked it up the source was putting out 800 kHz. With a bit more investigation he figured out how to reconfigure the support electronics to get that 10 Mhz source. We think you’re going to love reading about how he used a test crystal during the reconfiguration step.

Once he knew what he had he returned to the eBay seller and cleared out the rest of his stock.

[Thanks DIY DSP]

RC Airplane Made from Political signs

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Whatever candidate (if any) you’re in favor of, we could bet that you’re probably tired of seeing advertisements and political signs everywhere. [Mark] wrote in with a hack that allows you to actually use these signs for something fun, making a RC airplane!

[Mark] gives a full bill of materials in his article, but the featured component is campaign sign. This isn’t LawyerADay, so we’re not sure of the legality of taking them. After election day at least, it’s doubtful anyone will care. Of course you’ll also need a motor, prop, and RC controls, as well as some dowels to attach the tail section to the main body, so don’t buy the “campaign promise” that this is a free airplane.

CAD diagrams are available of the cutouts, as well as how to cut the signs to form hinges without any other parts. This is quite clever, and a video of the plane in action on a table is available on the site. According to [Mark], no video was rolling on its test flight, but it did fly before some interference grounded the plane. Hopefully he’ll be able to get some footage of it in action soon!

Putting 300 watts of LEDs on an RC plane

Being a member of the FPVlab forums, [HugeOne] is really in to strapping a video camera to RC airplanes and flying around by the seat of his pants. He’s also in to flying his plane at night. Combine these two interests, and you’ve got 300 watts of LEDs flying around at night, most likely causing a spike in UFO reports in [HugeOne]’s native Quebec.

The main issue with putting 16 CREE XM-L LEDs in such a confined space is the issue of heat; even though these LEDs are amazingly efficient, they still produce a good amount of heat. [HugeOne] solved this problem by soldering these LEDs to a piece of copper pipe and connecting two radiators to his plane for liquid cooling.

The result is a small, lightweight LED array capable of producing more than 20,000 lumens flying around the wilds of Quebec. This greatly improves [HugeOne]’s night flying ability (video after the break), and has surely annoyed the local police department with an increase in UFO reports.

Does anyone know how bright the nav and landing lights on single-engine passenger airplanes are?

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Autonomous fixed-wing drone threads the needled in a parking garage

We’ve got something of a love affair going on with quadcopters, but there’s still room for a little something on the side. This fixed-wing drone can pull off some pretty amazing navigation. MIT’s Robust Robotics Group is showing off the work they’ve done with the plane, culminating in a death-defying flight through a parking garage (video after the break). This may not sound like a huge accomplishment, but consider that the wingspan is over two meters and repeated runs at the same circuit brought it within centimeters of clipping support columns.

Unlike the precision quadcopters which depend on stationary high-speed cameras for feedback, this drone is self-contained. It does depend on starting out with a map of its environment, using this in conjunction with a laser rangefinder and inertial sensors to plot its route and adjust as necessary. We think the thing must have to plan a lot further ahead than a quadcopter since it lacks the ability to put on the brakes and hover. This is, however, one of the strengths of the design. Since it uses a fixed-wing approach it can stay in air much longer than a quadcopter with the same battery capacity.

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Geigers on a plane

[Thomas] took a Geiger counter he built on a plane. Why? Because he can, much to the chagrin of airport security.

[Thomas]’ Geiger counter is built around an old Russian SBT-10A detector containing ten separate Geiger tubes. This tube was connected to a circuit containing a LiPo battery, a few high-voltage components, and an audio jack connected to the tubes themselves. When alpha, beta, or gamma radiation hits one of the Geiger tubes, an enormous click is sent to the audio jack and into the microphone jack of a small netbook.

Right after boarding a plane in Dublin, [Thomas] booted up his computer, started recording in Audacity, plugged in his Geiger counter, and stored his experiment safely in the overhead compartment. After landing in Prague a few hours later, [Thomas] saved the 247 MB .WAV file and began working on a way to convert clicks in an audio track into usable data.

The audio output on the Geiger counter overloaded the mic input on his netbook, making ‘event detection’ very easy with a small C app. After plotting all the data (seen above), [Thomas] had a complete record of the radiation on his 2-hour flight.

Because there was far less atmosphere to absorb cosmic radiation, [Thomas]’ radiation dose was 9.1 microsieverts. Much more than at sea level, but nothing even air crews need to worry about.

Adding payload to an RC cessna

For just a few bucks you can add a payload to your flying toys. In this case it’s a Cessna RC plane which now has an added surprise. The first thing to be dropped was a parachute with a weight on it (for testing purposes). But there are hints of future projects that will use the same system for different purposes.

As you can see in the image above, the system depends on an additional compartment attached to the bottom of the plane. It was built from foam board to keep the weight down and connects using rare earth magnets. The bottom of the enclosure acts as the door, hinging on a servo motor with a bamboo skewer as the axle. So far the test drops have gone pretty well, but some more work needs to be done with the parachute design. It only opens about 60% of the time. We can sympathize, having had to work out some of our own parachute issues.

Don’t miss video from the plane as well as the ground after the break.

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Automatic airplane tracking; what radar-systems engineers do for kicks

[G. Eric Rogers] is a radar-systems engineer who just happens to live within sight of the aircraft approach path for the local airport. We wonder if that was one of the criteria when looking for a home? Naturally, he wanted his own home-based system for tracking the airplanes. He ended up repurposing a motorized telescope for this purpose.

The system does not actually use Radar for tracking. Instead, the camera strapped to the telescope is feeding a video experimenter shield. A tracking algorithm analyzes the video and extrapolates vector data. From there, the base unit can be controlled by the Arduino via an RS232 interface.

There are some bugs in the system right now. The Arduino has something of an ADHD problem, losing interesting and going to sleep in the middle of the tracking process. [Eric’s] workaround uses the RS232 board to periodically reset the Arduino, but he hopes to squash this bug soon.