Talking To ISEE-3

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ISEE-3, the plucky interplanetary spacecraft fueled by the dreams of thousands of crowdfunding backers and hydrazine is now transmitting data to Earth.

Where all radio contact with ISEE-3 this year has only been a carrier frequency, the folks at the reboot project have successfully commanded ISSE via the huge Arecibo telescope to transmit data back to Earth. Usable data are now being received at 512 bits/second at ground stations in Germany, Kentucky, and California, surely being looked over by the ISEE reboot project engineers.

Simply transmitting the commands to put the data multiplexers into their engineering telemetry mode was no small task; a power amplifier needed to be built, shipped to Arecibo, and installed in the giant dome hanging over the Arecibo dish. The amplifier was only installed in the last day, during an earthquake, no less.

There’s still a lot of work to be done before the project can go any further; the team will need to check the status of the spacecraft from the data received, more systems will be checked out, and eventually the spacecraft will be commanded to perform a 17-hour long burn with its small thrusters, putting it on course to be captured by Earth some time in August.

It’s an amazing achievement to do any sort of communication on this scale, and now events in the ISEE-3 mission timeline will be coming rather quickly. We’re trying to organize a video/blog/cast thing with the team from NASA Ames or Morehead State, but the team is, understandably, a little busy right now.

Oinker is Twitter for HAMs

oinker

Have you ever wanted to send a quick message to your HAM radio buddies over the air but then realized you forgot your radio at home? [Troy] created Oinker to remedy this problem. Oinker is a Perl script that turns emails into audio.

The script monitors an email account for new messages and then uses the Festival text-to-speech engine to transform the text into audio. [Troy] runs Oinker on a Raspberry Pi, with the Pi’s audio output plugged directly into an inexpensive ham radio. The radio is then manually tuned to the desired transmit frequency. Whenever Oinker see’s a new email, that message is converted into speech and then output to the transmitter.

The script automatically appends your HAM radio call sign to the end of every message to ensure you stay within FCC regulations. Now whenever [Troy] runs into some bad traffic on the road, he can send a quick SMS to his email address and warn his HAM radio buddies to stay clear of the area.

Repairing a Damaged RC Rx Due to Reverse Polarity Power Input

Rx Receiver Repair

Once in a while all of us technocenti get a little complacent and do something that may be considered ‘dumb’ while working on a project…. like cutting the wrong side of a piece of wood or welding a bracket on in the wrong direction. [Santhosh] is human like everyone else and plugged in the power connector to his RC Receiver incorrectly, rendering the receiver useless. How will his Arduino-controlled Robot work without a functioning receiver?

[Santhosh] started by opening up the case to expose the circuit board and checking out the components inside. The first component in the power input path was a voltage regulator. Five volts DC was applied to the input side of the 3.3-volt regulator but only 1.21 came out the other end. Now that the problem was quickly identified the next step was to replace the faulty regulator. Purchasing an exact replacement would have been easy but cost both time and money. [Santhosh]‘s parts bin contained a similar regulator, a little larger than the original but the pinout was the same.

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Reading 2.4GHz Transmitters With An Arduino

QuadThere are a lot of cheap quadcopter kits out there, sold ready to fly with a transmitter and battery for right around $50 USD. One of the more popular of these micro quads is the V2X2 series. They are, unfortunately not compatible with any other radio protocol out there, but [Alexandre] has managed to use the transmitter included with his V202 quad to send data to an Arduino.

Like most quads, the transmitter that came with [Alexandre]‘s V202 operates on 2.4GHz. Listening in on that band required a little bit of hardware, in this case a nordic Semiconductors nRF24L01p. Attached to this chip is a regular ‘ol Arduino running a bit of code that includes [Alexandre]‘s V202 library.

Right now, the build can detect if the quad is bound or not, and read the current position of the throttle, yaw, pitch, and roll, as well as all the associated trims. It’s just the beginnings of [Alexandre]‘s project, but his eventual goal is to build an Arduino bot based on the code, complete with RC servos. Not bad for a transmitter that will be utterly useless when the microquad eventually breaks.

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DIY Ultra Wideband Impulse Synthetic Aperture Radar And A MakerBot

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What could possibly be better than printing out a few low-resolution voxels on a MakerBot? A whole lot of things, but how about getting those voxels with your own synthetic aperture radar? That’s what [Gregory Charvat] has been up to, and he’s documented the entire process for us.

The build began with an ultra wideband impulse radar we saw a while ago. The radar is built from scraps [Greg] picked up on eBay, and is able to image a scene in the time domain, creating nice linear sweeps on a MATLAB plot when [Greg] runs in front of the horns.

With an impulse radar under his belt, [Greg] moved up the technological ladder to something that can produce vaguely intelligible images with his setup. The synthetic aperture radar made from putting his radar horns on the carriage of a garage door opener. The horns slowly scan back and forth along the linear rail, taking single impulse readings and adding them together in an image. In the video below, [Greg] is able to image a few pieces of copper pipe only a few inches in diameter. The necessary equipment for this build only cost [Greg] a few hundred bucks at the Dayton Hamvention, and a similar setup could be put together for even less.

If building an X band impulse synthetic aperture radar isn’t impressive enough. [Greg] also 3D printed one of his radar images on a MakerBot. That’s just applying stlwrite to the 2D radar image and feeding it into MakerWare. Gotta have that blog cred, doe. It also makes for the best headline I’ve ever written.

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Airchat, The Wireless Mesh Network From Lulzlabs

Airchat

With the lessons learned from the Egyptian, Libyan, and Syrian revolutions, a few hardware and software hackers over at Lulzlabs have taken it upon themselves to create a free-as-in-beer and free-as-in-speech digital communications protocol that doesn’t deal with expensive, highly-surveilled commercial and government controlled infrastructure. They call it Airchat, and it’s an impressive piece of work if you don’t care about silly things like ‘laws’.

Before going any further, we have to say yes, this does use amateur radio bands, and yes, they’re using (optional) encryption, and no, the team behind Airchat isn’t complying with all FCC and other amateur radio rules and regulations. Officially, we have to say the FCC (and similar agencies in other countries) have been granted the power – by the people – to regulate the radio spectrum, and you really shouldn’t disobey them. Notice the phrasing in that last sentence, and draw your own philosophical conclusions.

Airchat uses an off the shelf amateur transmitter, a Yaesu 897D in the example video below although a $30 Chinese handheld radio will do, to create a mesh network between other Airchat users running the same software. The protocol is based on the Lulzpacket, a few bits of information that give the message error correction and a random code to identify the packet. Each node in this mesh network is defined by it’s ability to decrypt messages. There’s no hardware ID, and no plain text transmitter identification. It’s the mesh network you want if you’re under the thumb of an oppressive government.

Airchat has already been used to play chess with people 180 miles away, controlled a 3D printer over 80 miles, and has been used to share pictures and voice chats. It’s still a proof of concept, and the example use cases – NGOs working in Africa, disaster response, and expedition base camps – are noble enough to not dismiss this entirely.

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ISEE-3 Dream Team Needs Your Help

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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