GPS And SDR Combine Forces

Software-defined radio (or SDR) is a relatively new (to average tinkerers, at least) way of sending and receiving radio signals. The interest in SDR exploded recently with the realization that cheap USB TV tuner cards could be used to start exploring the frequency spectrum at an extremely reduced cost. One of the reasons that this is so advantageous is because of all of the options that a general-purpose computer opens up that go beyond transmitting and receiving, as [Chris] shows with his project that ties SDR together with GPS.

The goal of the project was to automatically tune a radio to the local police department’s frequency, regardless of location. To do this, a GPS receiver on a computer reports information about the current location. A JavaScript program feeds the location data to the SDR, which automatically tunes to the local emergency services frequencies. Of course, this relies on good data for what those frequencies are, but this is public information in most cases (at least in the US).

There are a lot of opportunities here for anyone with SDR. Maybe an emergency alert system that can tune to weather broadcasts if there’s a weather alert, or any of a number of other captivating projects. As for this project, [Chris] plans to use Google’s voice recognition software to transcribe the broadcasts as well. The world of SDR is at your fingertips to do anything you can imagine! And, if you’re looking to get started in it, be sure to check out the original post covering those USB TV tuner dongles.

Hackaday Prize Entry: Reverse GPS

Every time you watch a SpaceX livestream to see a roaring success or fireball on a barge (pick your poison), you probably see a few cubesats go up. Everytime you watch a Soyuz launch that is inexplicably on liveleak.com before anywhere else, you’re seeing a few cubesats go up. There are now hundreds of these 10 cm satellites in orbit, and SatNogs, the winner of the Hackaday Prize a two years ago, gives all these cubesats a global network of ground stations.

There is one significant problem with a global network of satellite tracking ground stations: you need to know the orbit of all these cubesats. This, as with all Low Earth Orbit deployments that do not have thrusters and rarely have attitude control, is a problem. These cubesats are tumbling through the rarefied atmosphere, leading to orbits that are unpredictable over several months.

[hornig] is working on a solution to the problem of tracking hundreds of cubesats that is, simply, reverse GPS. Instead of using multiple satellites to determine a position on Earth, this system is using multiple receiving stations on Earth’s surface to determine the orbit of a satellite.

The hardware for [hornig]’s Distributed Ground Station Network is as simple as you would expect. It’s just an RTL-SDR TV tuner USB dongle, a few antennas, a GPS receiver, and a Raspberry Pi connected to the Internet. This device needs to be simple; unlike SatNogs, where single base station in the middle of nowhere can still receive data from cubesats, this system needs multiple receivers all within the view of a satellite.

The modern system of GPS satellites is one of the greatest technological achievements of all time. Not only did the US need to put highly accurate clocks in orbit, the designers of the system needed to take into account relativistic effects. Doing GPS in reverse – determining the orbit of satellites on the ground – is likewise a very impressive project, and something that is certainly a contender for this year’s Hackaday Prize.

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Hackaday Links: June 12, 2016

The Navy is doing some crazy stuff out in China Lake. They were planning to test something out that could potentially make GPS unusable from San Diego to Las Vegas to San Francisco. Those plans were cancelled for ‘internal’ reasons. They will be testing something in Indiana shortly, though. What are they doing? Who knows. That’s what idle speculation in the comments section is for.

3D Hubs, the distributed ‘3D printing service’ thing, now has 30,000 machines distributed around the globe. They also put together the definitive guide to 3D printing recently. For just about everyone reading this, a ‘introduction to 3D printing’ is old news, but this is a very good guide for telling your weird aunt what you’re building in the basement. Forward this one to your family on Facebook.

This one is amazing. Over on Hackaday.io, [Arsenijs] is working on a Raspberry Pi project. It uses a Raspberry Pi, and several accessories and components to make this Raspberry Pi project work. This Raspberry Pi project is already getting far more than the usual number of likes and follows, making this one of the most interesting Raspberry Pi projects in recent memory.

Moog is re-releasing the Minimoog, the original Moog synth from 1970. That’s cool, but what about a DIY Minimoog? That’s what [Scott Rider] is doing with the Crowminius Analog Music Synthesizer on Kickstarter. It’s an analog synth that’s more or less a Minimoog with MIDI, and one of the Kickstarter rewards is a bare PCB.

The future is dancing robots, so here’s a servo-driven Stewart platform that is sure to bring on the robot apocalypse.

What do you do when you need to get your Hackaday fix, but all you have is a laptop from 1995 and a dial-up modem? The Hackaday Retro Edition, of course. That’s a bunch of retro Hackaday posts, posted five at a time, with all the CSS and JavaScript cruft stripped. We’re always interested to see the old machines that are pulling the retro edition down, and [djnikochan] has the latest entry. He found a Thinkpad 380ED from 1997 at the Goodwill store for $15. The RAM was upgraded with a 64MB SIMM, giving this machine a total of 80MB. The Hackaday Retro Edition is viewable with IE 5.5 over a trusty PCMICA WiFi card. Awesome job, and we love to see old iron rendering the retro edition. Send some pics in if you get your old battlestation to load it.

Netbook Finds New Home in a Jaguar Dashboard

You’d figure a luxury car like a Jaguar would have a high-end infotainment system. [RichTatham]’s Jag did, but the trouble was that it was a high-end system when a cassette deck and trunk-mounted CD changer were big deals. So naturally, he saw this as a great reason to modernize the system by grafting a netbook into the Jag’s dash. The results are fantastic!

Even though the Jag’s original system didn’t have much left that made it into the final project — the navigation system, CD changer, phone and even the amps ended up on the scrap heap — at least the dashboard instrument cluster proved to be very amenable to his mods. By substituting a climate control cluster from another model into his car, he was able to free up tons of space for the netbook’s 8″ display. A custom bezel and some clever brackets completed the head-end of the new system, and the look is as close to a factory install as you’re likely to find in an aftermarket mod. With the netbook stashed in the bay vacated by the OEM system, a GPS dongle, and a USB sound card connected to a 5.1 amp using the original speakers this jag is ready to bump. We bet that the system sounds as good as it looks, and with the added functionality of a Windows PC to boot.

For obvious reasons, lots of computers make it into hackers’ dashboards, whether they be Windows like this one, Samsung tablets or Nexus tablets running Android, and even phones. But [Rich]’s build is top notch, and takes in-car integrations to the next level.

[via r/diy]

Shipwreck Exploration Vessels Fit in Minivan; Stream to Internet

Having to work away from the convenience of a workshop can be tough. But it’s sometimes unavoidable and it always means planning ahead. When the work area also happens to be 150m under a lake’s surface, it’s much more of a challenge – but it’s both doable and more accessible than you might think. To prove it, this DIY research vessel will be part of the robotic exploration of an underwater shipwreck. It is complete with an Ethernet bridge, long-range wireless communications, remotely operated underwater vehicle (ROV), the ability to hold a position, and more. The best part? It can all be packed up and fit into a minivan. We can’t put it any better than the folks at the OpenROV Forums:

In just over a week (June 6th – 9th), a bunch of people from OpenROV are going to attempt to dive a set of specially modified deep-capable ROVs to a 50m-long shipwreck at a depth of 150m below lake Tahoe. We’ll be using a deployment architecture that we’ve been perfecting over the years that involves a very small boat keeping station over the dive site while the rest of the people on the expedition run the mission from a remote location via long-range broadband radio. Since the mission control site will have an internet connection, we’ll be able to live stream the entire dive over the internet.

OpenROV DIY Research VesselThe purpose of the design was “to demonstrate that many of the capabilities one might think would require a large research vessel can actually be achieved with off-the-shelf parts that are more portable and much less expensive. […] There’s a lot to discover down there, and the technology readily available these days can allow us to explore it.” This mindset happens to wonderfully complement the kickoff of the Citizen Scientist Challenge portion of the 2016 Hackaday Prize.

For those times when your work can remain on solid ground, one method is to sidestep the entire issue of working away from the workshop by simply making your whole work area mobile like this incredible conversion of a truck trailer to a mobile lab.

The Foghorn Requiem

Foghorns have been a part of maritime history since the 19th century, providing much needed safety during inclement weather to mariners out at sea. Over time, their relevance has slowly reduced, with advanced navigational aids taking over the task of keeping ships and sailors safe.

The sounds of the foghorns are slowly dying out. Artists [Joshua Portway] and [Lise Autogena] put together the Foghorn Requiem, a project which culminated on June 22nd 2013, with an armada of more than 50 ships gathered on the North Sea to perform an ambitious musical score, marking the disappearance of the sound of the foghorn from the UK’s coastal landscape.

ship_layoutUp close, a foghorn is loud enough to knock you off your shoes. But over a distance, its sound takes on a soulful, melancholy quality, shaped by the terrain that it passes over. The artists tried capturing this quality of the foghorn, with help from composer [Orlando Gough] who created a special score for the performance. It brought together three Brass Bands – the Felling Band, the Westoe Band and the NASUWT Riverside Band, almost 50 ships at sea and the Souter Lighthouse Foghorn to play the score.

Each of the more than 50 vessels were outfitted with a custom built, tunable foghorn, actuated by a controller box consisting of a TI Launchpad with GPS, RTC, Xbee radio and relay modules. Because of the great distances between the ships and the audience on land, the devices needed to compensate for their relative position and adjust the time that they play the foghorn to offset for travel time of the sound. Each controller had its specific score saved on on-board storage, with all controllers synchronized to a common real time clock.

Marine radios were used to communicate with all the ships, informing them when to turn on the controllers, about 10 minutes from the start of the performance. Each device then used its GPS position to calculate its distance from the pre-programmed audience location, and computed how many seconds ahead it had to play its horn for the sound to be heard in time on the shore. The controllers then waited for a pre-programmed time to start playing their individual foghorn notes. The cool thing about the idea was that no communication was required – it was all based on time. Check out the video of the making of the Foghorn Requiem after the break, and here’s a link to the audio track of the final performance.

This is a slightly different approach compared to the Super Massive Musical Instrument that we posted about earlier.

Continue reading “The Foghorn Requiem”

Autonomous Truck Teaches Itself To Powerslide

When you’re a teenager new to the sensations of driving, it seems counterintuitive to “turn into the skid”, but once you’ve got a few winters of driving under your belt, you’re drifting like a pro. We learn by experience, and as it turns out, so does this fully autonomous power-sliding rally truck.

Figuring out how to handle friction-optional roadways is entirely the point of the AutoRally project at Georgia Tech, which puts a seriously teched-up 1/5 scale rally truck through its paces on an outdoor dirt track. Equipped with high-precision IMU, high-resolution GPS, dual front-facing cameras, and Hall-effect sensors on each wheel sampled at 70 Hz, the on-board Quad-core i7 knows exactly where the vehicle is and what the relationship between it and the track is at all times. There’s no external sensing or computing – everything needed to run the track is in the 21 kg truck. The video below shows how the truck navigates the oval track on its own with one simple goal – keep the target speed as close to 8 meters per second as possible. The truck handles the red Georgia clay like a boss, dealing not only with differing surface conditions but also with bright-to-dark lighting transitions. So far the truck only appears to handle an oval track, but our bet is that a more complex track is the next step for the platform.

While we really like the ride-on scale of this autonomous chase vehicle, other than that there haven’t been too many non-corporate self-driving vehicle hacks around here lately. Let’s hope that AutoRally is an indication that the hackers haven’t ceded the field to Google entirely. Why let them have all the fun?

Continue reading “Autonomous Truck Teaches Itself To Powerslide”