Extrinsic Motivation: Smart Antenna Tracker for R/C Aircraft

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Long distance FPV (First Person View) flying can be a handful. Keeping a video feed alive generally requires a high gain directional antenna. Going directional creates the chore of keeping the antenna pointed at the aircraft. [Brandon's] smart antenna tracker is designed to do all that automatically. What witchcraft is this, you ask? The answer is actually quite simple: Telemetry! Many flight control systems have an optional telemetry transmitter. [Brandon] is using the 3DRobotics APM or PixHawk systems, which use 3DR’s 915 MHz radios.

The airborne radio sends telemetry data, including aircraft latitude and longitude down to a ground station. Equipped with a receiver for this data and a GPS of its own, the smart antenna tracker knows the exact position, heading and velocity of the aircraft. Using a pan and tilt mount, the smart antenna tracker can then point the antenna directly at the airborne system. Since the FPV antenna is co-located on the pan tilt mount, it will also point at the aircraft and maintain a good video link.

One of the gotchas with a system like this is dealing with an aircraft that is flying directly overhead. The plane or rotorcraft can fly by faster than the antenna system can move. There are a few commercial systems out there that handle this by switching to a lower gain omnidirectional whip antenna when the aircraft is close in. This would be a great addition to [Brandon's] design.

A Raspberry Pi Helmet Cam with GPS Logging

20140126_222809-1 Over the last 20 years, [Martin] has been recording snowboarding runs with a standard helmet cam. It was good but he felt like he could improve upon the design by building his own version and logging additional data values like speed, temperature, altitude, and GPS. In the video shown after the break, a first person perspective is displayed with a GPS overlay documenting the paths that were taken through the snow. [Martin] accomplished this by using a python module called picamera to start the video capture and writing the location to a data file. He then modified the program to read the current frame number and sync GPS points to an exact position in the video. MEncoder is used to join the images together into one media file.

The original design was based on the Raspberry Pi GPS Car Dash Cam [Martin] developed a few months earlier. The code in this helmet cam utilizes many of the same functions surrounding the gathering of GPS data points, recording video, and generating the overlay. What made this project different though were the challenges involved. For example, a camera inside a car rarely has to deal with extreme drops in temperature or the wet weather conditions of a snowy mountain. The outside of the vehicle may get battered from the snow, but the camera remains relatively safe from exposure. In order to test the Raspberry Pi before venturing into the cold, [Martin] stuck the computer in the freezer to see what would happen. Luckily it worked perfectly.

Click past the break for the rest of the story.

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THP Entry: The Everything RC Transmitter

OSRC With few exceptions, most of The Hackaday Prize are things we really haven’t seen much of before: base-3 computers that have been relegated to the history books, extremely odd 3D printers, and fancy, new IoT devices are the norm. The OSRC is not a new project to us. We saw it once in 2011 and again a year later. What makes the OSRC an interesting project for The Hackaday Prize isn’t the fact that it’s the most advanced RC transmitter ever created. Creating that was evidently the easy part. The OSRC could use a big financial kick in the pants, and if [Demetris] wins, we’d guess he wouldn’t be taking that ride to space. Rather, he’d be taking the cash prize to get his ultimate transmitter into large-scale manufacturing and out into the wild.

While at first glance the base model OSRC seems expensive at about $6-700 USD, consider this: a six-channel transmitter from an excellent brand costs about $120 USD. Nine channels will run you about $400. The OSRC is a forty channel radio. The sticks are capable of force feedback, and of course the ‘pro’ model of the OSRC has that wonderful screen, capable of displaying video from an FPV camera, a GPS/map overlay, or an incredibly extensive telemetry display. There are multi-thousand dollar avionics for real airplanes out there that have a smaller feature set, and that’s not hyperbole.

A few months ago, [Demetris] was interviewed by the awesome people at Flite Test. That (highly suggested) video is embedded below.


SpaceWrencherThe project featured in this post is an entry in The Hackaday Prize. Build something awesome and win a trip to space or hundreds of other prizes.

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Hackaday Links: June 29, 2014

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Ever see a really cool build on YouTube with no build details at all? Frustrating, right? That’s us with the NES Keytar covering the Game of Thrones theme. He’s using a Raspi with the sound chip in the NES to do live chiptunes. Freakin’ awesome. There’s also the ST:TNG theme as well.

A few years ago the folks at Oculus had an idea – because of cellphones, small, high resolution displays are really cheap, so why not make VR goggles? At Google IO this week someone figured out everyone already has a cellphone, so just wrap it in some cardboard and call it a set of VR goggles. You can get a kit here, but the only difficult to source components are the lenses.

What happens when you put liquid nitrogen under a vacuum? Well, it should evaporate more, get colder, and freeze. Then it breaks up into solid nitrogen snow. No idea what you would do with this, but there ‘ya go. Oh, [NC], we’re going to need a writeup of that LN2 generator.

About a month ago, the House4Hack hackerspace in South Africa told us of their plans to bring a glider down from 20km above the Earth. They finally launched it, The CAA only allowed them to glide back from 6km (20,000 feet), but even from there the foam glider hit 230kph (124 knots). That’s a little impressive for a foam FPV platform, and we’re betting something with a larger wingspan would probably break a spar or something. Shout out to HABEX.

All the electronic dice projects we’ve seen have one thing in common: they’re not cubes. Thus uberdice. It’s six nine-pixel displays on the faces of a cube, powered by a battery, and controlled by an accelerometer. Yes, it is by far the most complicated die ever made, but it does look cool.

R/C Plane Flies with a Cockpit View

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That’s not a jet jockey making a low altitude turn up there. In fact, the pilot has his feet planted firmly on the ground. [Reliku] has built a radio controlled BAE Hawk which is flown via First Person View (FPV). FPV models often have a small camera mounted on the exterior of the craft. This camera gives a great field of view, but it isn’t exactly how full scale planes are flown.

[Reliku] took it to the next level by creating a scale cockpit for his plane. The cockpit is accurate to the real BAE Hawk T2, and features back lit simulated screens. Even the pilot got the FPV treatment. Micro servos move the pilot’s right hand in response to aileron and elevator inputs from the radio control system. The pilot’s head has been replaced with the FPV camera, which is mounted on a pan tilt unit. Pan and tilt are controlled by a head tracking system attached to [Reliku's] video goggles. The entire experience is very immersive.

All this is built into a Hobbyking BAE Hawk Electric Ducted Fan (EDF) model, so space is at a premium. Even with the Hawk’s relatively large cockpit, [Reliku] found he was tight on space. While attempting to keep the cockpit scale from the pilot’s view, he found he was barely able to fit a single seat cockpit into a space designed for two! Adding all these modifications to a plane and still keeping the model flyable was not easy, as displayed by [Reliku's] earlier attempt with an F-16.

The ends do justify the means though, as the final model looks great. We’d love to see those static cockpit displays replaced with small LCD or OLED panels for an even more realistic experience!

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A Hexacopter with FPV

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[Robert's] been hard at work becoming a hexacopter expert over the past two years, and he’s offered up a retrospective of his multi rotor build experience since he first clicked the “buy” button on Hobbyking. He’s come a long way from his first build, which used inexpensive carbon rods and 3D-printed parts for a frame, supported by scrap wood and hot glue. It met its end in his car; exposed to direct sunlight, the 3D-printed components melted.

The latest iteration—seen above on the right—is a complete redesign, with a laser-cut frame that dramatically reduced the overall weight and new “Donkey” motors off Hobbyking. It’s strong enough to lift a 1.6kg (3.5lbs) stuffed animal suspended from a rope! Most recently [Robert] has worked out streaming first-person video after fitting a camera to the hexacopter via a 3D-printed attachment and pairing the experience with Zeiss Cinemizer 3D glasses. He still has some bugs to work out, namely screws loosening from vibrations and adding a HUD to the display so he’ll know when the battery levels are low. You can see the poor teddy bear getting hanged along with some other videos, including the first-person video flight, after the break.

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Remote Control FPV cockpit

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FPV flying, for how awesome it actually is, still consists of fiddling around with a remote control transmitter and either wearing video goggles or squinting into a screen. Awesome, yes, but not as cool as [Brett Hays]‘s enclosed cockpit ground station. It’s a trailerable flight sim that allows you to have the same experience of flying an aircraft over your local terrain without actually leaving the ground.

The centerpiece for this build is a 42 inch flat screen TV that was picked up for $160. This was placed at the front of a large plywood and 2×2 box along with a computer joystick, throttle, and rudder controls.

The pots inside the controls needed to be switched out to match the resistance of the ones inside an old Futaba transmitter. From there, completing the the cockpit was just a matter of fabricating a few panels for a video switcher, gear retract lever, flaps. and RC radio settings.

It’s a truly amazing build and when placed on a trailer towed by [Brett]‘s jeep, has the potential to be the closest thing to flying a manned aircraft you can get without a pilot’s license.

Videos of the cockpit in action below.

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