ISEE-3 Dream Team Needs Your Help

April 28, 2014 by Adam Fabio 10 Comments

ISEE-3 Moon flyby

The mission to save ISEE-3 has is underway. The ISEE-3 Reboot Project has posted a crowdfunding campaign on Rockethub. When we first covered the ISEE-3 story no one had heard from it since 2008. Since then AMSAT-DL, an amateur radio group in Germany has received signals from the probe.

The ISEE-3 Reboot Project is being managed by [Dennis Wingo] and [Keith Cowing], the same two men who spearheaded the effort to recover NASA’s Lunar Orbiter images from old magnetic tapes. They did most of their work using restored 1960’s equipment in a vacant McDonald’s.

The goal of the ISEE Reboot Project is to return ISEE-3 to its original Earth/Sun Lagrange point L1 orbit. Once safely back in orbit, it will be used for STEM education, amateur radio solar predictions, and for science about the sun. In [Dennis Wingo’s] own words

If we can do this, we will have an open source, publicly accessible satellite data stream of the first open source satellite above Low Earth Orbit.

[Wingo] and [Cowing] aren’t alone in this effort; they are working with a venerable dream team. In addition to getting the nod from NASA, the team also has the help of [Dr. Robert Farquhar], the orbital dynamics guru who originally designed ISEE-3’s comet intercept orbit . [Farquhar] has an extremely personal reason to participate in this project. In 1982 he “borrowed” the satellite to go comet hunting. Once that mission was complete, he promised to give ISEE-3 back. [Dr. Farquhar] and his team designed the maneuvers required to bring ISEE-3 back to L1 orbit back in the 1980’s. This includes a breathtaking moon flyby at an altitude of less than 50 km. Seriously, we want to see this guy’s KSP missions.

Communicating with the ISEE-3 is going to take some serious power and antenna gain. The project has this in the form of a 21 meter dish at Moorehead State University in Kentucky, USA, and the Arecibo Observatory. Arecibo should be well-known to our readers by now. Moorehead and Arecibo have both received signals from ISEE-3. The reboot project team is also working directly with the AMSAT-DL team in Germany.

If this effort seems a bit rushed, that’s because time is very short. To implement [Dr. Farquhar’s] plan, ISEE-3 must fire its thrusters by late June 2014. In just two months the team needs to create software to implement ISEE-3’s communications protocols, obtain and install transmitters at Moorehead and Aricibo, and send some basic commands to the craft. Only then can they begin to ascertain ISEE-3’s overall health in preparation for a thruster burn.

If the ISEE-3 Reboot Project succeeds, we’ll have an accessible satellite well outside of low Earth orbit. If it fails, Issac Newton will remain at the helm. ISEE-3 will fly right past Earth, not to be seen again until August 2029.

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Building A Software Defined Radio With A Teensy

April 25, 2014 by Brian Benchoff 21 Comments

[Rich, VE3MKC] has been wanting to get into Software Defined Radio for a while now, but didn’t want to go the usual PC route. He initially thought the Raspberry Pi would be the best platform for a small, embedded device that could manipulate audio, but after discovering the ARM-powered Teensy 3.0, had an entirely different project in mind.

[Rich] is using a SoftRock SDR to take RF from an antenna and downconvert it into the audio range. Doing DSP for SDR is fairly computationally intensive, but he found a Teensy 3.0 with the audio adapter board was more than up to the task.

So far, [Rich] is running the audio from the SoftRock to the Teensy where the audio is digitized and multiplied with a VFO, sent through a filter and then sent to the output of the headphone jack to a speaker. The volume pot on the audio adapter board is used to tune the VFO, something [Rich] be replacing with a proper encoder sometime in the future.

In the videos below, you can see [Rich] listening in on a contest with a tiny TFT display showing everybody on the air. It’s a very cool build, and even though it’s still very early in development, there’s still a whole lot of CPU cycles for the Teensy to do some very cool stuff.

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[Balint]’s GNU Radio Tutorials

April 22, 2014 by Brian Benchoff 15 Comments

Waterfall

[Balint] has a bit of history in dealing with software defined radios and cheap USB TV tuners turned into what would have been very expensive hardware a few years ago. Now [Balint] is finally posting a few really great GNU Radio tutorials, aimed at getting software defined radio beginners up and running with some of the coolest hardware around today.

[Balint] is well-known around these parts for being the first person to create a GNU Radio source block for the implausibly inexpensive USB TV tuners, allowing anyone with $20 and enough patience to wait for a package from China to listen in on everything from 22 to 2200 MHz. There’s a lot of interesting stuff happening in that band, including the ACARS messages between airliners and traffic control, something that allowed [Balint] to play air traffic controller with a minimal amount of hardware.

Right now the tutorials are geared towards the absolute beginner, starting at the beginning with getting GNU Radio up and running. From there the tutorials continue to receiving FM radio, and with a small hardware investment, even transmitting over multiple frequencies.

It’s not much of an understatement to say software defined radio is one of the most versatile and fun projects out there. [Balint] even demonstrated triggering restaurant pagers with a simple SDR project, a fun project that is sure to annoy his coworkers.

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Unlocking Your Computer With A Leonardo And An NFC Shield

April 1, 2014 by Mathieu Stephan 21 Comments

Manually typing your login password every time you need to login on your computer can get annoying, especially if it is long and complex. To tackle this problem [Lewis] assembled an NFC computer unlocker by using an Arduino Leonardo together with an NFC shield. As the latter doesn’t come with its headers soldered, a little bit of handy work was required.

A custom enclosure was printed in order to house the two boards together and discretely mount them under a desk for easy use. Luckily enough very few code was needed as [Lewis] used the Adafruit NFC library. The main program basically scans for nearby NFC cards, compares their (big-endianned) UIDs against a memory stored-one and enters a stored password upon match. We think it is a nice first project for the new generation of hobbyists out there. This is along the same lines as the project we saw in September.

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Sniffing PH Sensor RF Signals For Feedback Re: Your Esophagus

March 31, 2014 by Mathieu Stephan 8 Comments

For about a week [Justin] had a wireless acidity level sensor in his esophagus and a pager-looking RF receiver in his pocket. So he naturally decided to use an RTL-SDR dongle to sniff the signals coming out of him. As most of our Hackaday readers know, these cheap RTL2382U-based DVB-T receivers are very handy when it comes to listening to anything between 50MHz and 1800MHz. [Justin] actually did a great job at listing all the things these receivers can be used for (aircraft traffic monitoring, weather images download, electric meter reading, pacemaker monitoring…).

After some Googling he managed to find his Bravo pH sensor user’s guide and therefore discovered its main frequency and modulation scheme (433.92MHz / ASK). [Justin] then used gqrx and Audacity to manually decode the packets before writing a browser-based tool which uses an audio file. Finally, a few additional hours of thinking allowed him to extract his dear esophagus’ pH value.

Build Your Own Radio Clock Transmitter

March 22, 2014 by Brian Benchoff 75 Comments

Deep in the Colorado foothills, there are two radio transmitters that control the time on millions of clocks all across North America. It’s WWVB, the NIST time signal radio station that sends the time from several atomic clocks over the airwaves to radio controlled clocks across the continent. You might think replicating a 70 kW, multi-million dollar radio transmitter to set your own clock might be out of reach, but with a single ATtiny45, just about everything is possible.

Even though WWVB has enough power to set clocks in LA, New York, and the far reaches of Canada, even a pitifully underpowered transmitter – such as a microcontroller with a long wire attached to a pin PWMing at 60kHz – will be more than enough to overpower the official signal and set a custom time on a WWVB-controlled clock. This signal must be modulated, of course, and the most common radio controlled clocks use an extremely simple amplitude modulation that can be easily replicated by changing the duty cycle of the carrier. After that, it’s a simple matter of encoding the time signal.

The end result of this build is an extremely small one-chip device that can change the time of any remote-controlled clock. We can guess this would be useful if your radio controlled clock isn’t receiving a signal for some reason, but the fact that April 1st is just a few days away gives us a much, much better idea.

Radar Imaging In Your Garage: Synthetic Aperture Radar

March 17, 2014 by Gregory L. Charvat 48 Comments

Learn why you were pulled over, quantify the stealthiness of your favorite model aircraft, or see what various household items look like at 10 GHz. In this post we will describe the basics of Synthetic Aperture Radar (SAR) imaging, beginning with a historical perspective, showing the state of the art, and describing what can be done in your garage laboratory. Lets image with microwaves!

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