Open Source Modular Rocket Avionics Package

Cambridge postgraduate student [Adam Greig] helped design a rocket avionics system consisting of a series of disc-shaped PCBs arranged in a stack. There’s a lot that went into the system and you can get a good look at it all through the flickr album.

Built with the help of Cambridge University Spaceflight, the Martlet is a 3-staging sounding rocket that lifts to 15km/50K feet on Cesaroni Pro98 engines. [Adam]’s control system uses several Arm Cortex M4s on various boards rather than having just one brain controlling everything.

Each disc is a module that plays a specific role in the system. There are a couple of power supply boards sporting twin LTC2975 able to supply custom power to a dozen different circuits. The power system has a master control board also sporting an M4. There’s an IMU board with the guidance system — accelerometer, magnetometer, gyroscope, and barometer, all monitored by an algorithm that computes the rocket’s position and attitude in-flight. There’s a radio board with a GPS receiver and an ISM band radio transceiver for telemetry, as well as a datalogger with 10 thermocouple measurement channels. Engines are controlled by the pyro board which controls firing currents on four different channels. The vertical spacers also serve to transmit power and data to neighboring boards.

If you’re interested in learning more, check out the project’s code and schematics on [Adam]’s GitHub repository.

[Adam] is no stranger to these pages, with his Nerf Vulcan turret published a few years back, as well as his balloon tracking rig published more recently. Photos are CC-SA and can be found in [Adam]’s Flickr feed.

Amphibious Houseboat Hits the Open Road

What’s better than having your own houseboat? How about an amphibious houseboat? That’s exactly what [Theon Parseghian] is building in his driveway. It all started with a derelict 32-foot long houseboat. A 1967 model with a rusted steel hull, [Theon] originally bought it as a guest house.

[Theon] couldn’t let the boat rust away in his back yard though. Quickly decided to get it back on the open water…. and on the road. An amphibious houseboat. While looking for large tractor tires, [Theon] found an entire crop sprayer which hadn’t been used in years. This crop sprayer was a giant tricycle wheeled monster, with huge spray arms.

The original plan was to carve out a hole for the sprayer, and essentially drop the boat on the sprayer chassis. Things never quite work out as planned though. The sprayer was a bit too short, so it’s chassis was replaced with one from a school bus. The axle wasn’t quite long enough to clear the boat’s draft, so it was extended with custom steel wheel spacers.

The build is documented in a 7 part series on YouTube. The latest episode details the boat’s first drive under its own power. We’re not sure how street legal an amphibious houseboat would be, but [Theon] doesn’t have too far to drive, as there is a large lake just behind his shop in Upstate New York. The houseboat launches on August 23. Good luck [Theon]!

If a houseboat is too big for you, how about a barrel boat. If you’re into tiny boats, you could cross the Atlantic with a 42-inch vessel.

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Smart Speed Bumps Slow Only Speeding Cars

Like it or not speed bumps are an essential part of our road infrastructure especially in built-up places like near schools [Business Insider UK] reports non-Newtonian liquid filled speed bumps are being tested in Spain, Israel and Germany.

Traditional speed bumps do have their drawbacks; damage to the underside of low vehicles is common. While they should be uniform in dimensions, in practice they can vary significantly, making driving over unfamiliar bumps a bit unpredictable. This is all set to change with non-Newtonian bumps which are soft to drive over at slow speeds but for speeding drivers they harden up and act more like traditional bumps. This gives drivers following the letter of the law a better driving experience whilst still deterring speeding drivers..

Non-Newtonian materials are nothing new but we think this is a great way of purposing these type of materials. Roads are getting smart whether you like it or not. It’s time to embrace technology and improve our commutes.  Continue reading “Smart Speed Bumps Slow Only Speeding Cars”

Building An Ultralight Out Of Foam In A Basement

[Peter Sripol] is something of a legend in the DIY RC aircraft crowd. He’s friends with Flite Test, and there he built an enormous RC cargo plane that could easily carry a small child aloft. Now, [Peter] is aiming a bit higher. He’s building an ultralight — a manned ultralight — in his basement. It’s made out of insulation foam.

Yes, this ultralight is constructed out of insulation foam, but you can think of that as just a skin. The real structure here comes from a wooden frame that will be fiberglassed. The design of this aircraft is an electric, twin-engine biplane. The relevant calculations have already been done, and [Peter] is already flying an RC scale model of this craft. So far, everything is not as sketchy as it could be.

As with any, ‘guy builds an airplane in his basement’ story, there must be a significant amount of time dedicated to the legality, practicality, and engineering of said plane. First off, the legality. [Peter] is actually building an ultralight under Part 103. The certifications for a Part 103 ultralight are much more lenient than the next step up in FAA-certified aircraft, a light sport or experimental aircraft. An ultralight is not required to have an airworthiness certification, and pilots of ultralights are not required to pass any tests of aeronautical knowledge or hold a medical certificate. Yes, legally, any moron can jump in an ultralight and fly. Think about that the next time someone brings up the Part 107 ‘drone’ certification.

Next, the practicality and engineering. [Peter]’s plane can weigh a maximum of 254 pounds, and should not be capable of more than 55 knots in full power level flight, while having a stall speed that does not exceed 24 knots. This is slow for a Cessna, but just about right for the gigantic remote-controlled planes [Peter] has already built.  A few years ago, [Peter] built a gigantic remote-controlled cargo plane out of what is basically foam board and a few aluminum tubes. The construction of [Peter]’s ultralight will be a highly refined version of this. He’s using foam insulation sheets for the body of the fuselage, reinforced with plywood and poplar struts. This foam and wood build will be wrapped with carbon fiber and fiberglass sheet, epoxied, and hopefully painted with flames on the side.

The use of poplar is a bit curious for an ultralight aircraft. For the last hundred years, the default wood for aircraft has been either spruce or douglas fir. The reason for this choice is the strength to weight ratio; spruce and douglas fir have the highest strength to weight ratio of any other wood. Poplar, however, is ultimately stronger and available at his local home improvement store, even though it does weigh a bit more. If [Peter] can keep the weight down in other areas, poplar is an excellent choice due to cost and availability. The video (below) is unclear, but we can only hope [Peter] has read up on the strength of aircraft frames and the orientation of the grain of each structural member.

This is the first video in what will be an amazing build series, and [Peter] hopes to get this thing up in the air by September. If you’re concerned about [Peter]’s safety, he’s also put up a GoFundMe page for a parachute. [Peter]’s going to fly this thing if you complain or concern troll or not, so donate a dollar for the parachute if you’re that concerned.

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Hackaday Prize Entry: Powered Running Stroller Keeps You Running

Types of strollers called ‘running strollers’ exist to make it possible to bring your toddlers along for your run but try it with two four-year old, 38 lb young ones, against the wind, and up enough hills and you’ll quickly lose steam. [Andrew Clink]’s and his wife’s solution? Modify the stroller to be a self-powered roadrunner.

[Andrew]’s hackaday.io build logs are detailed, including design, calculations, schematics, 3D printing files, fails and retries, and more. Power is provided by a bank of lithium-ion batteries that drive a brushless motor. The motor turns the stroller’s front wheel using a toothed belt around a small motor pulley and a larger 3D printed wheel pulley, providing a 13.92:1 gear ratio. [Andrew] considered a number of methods for steering, and even tried a few, but given that his paths are mostly straight lines, small adjustments by hand are all that’s needed. For the possibility of the stroller getting away from him for whatever reason, [Andrew] wrote an iOS app for his phone that makes use of the Bluetooth LE Proximity profile (PDF). It communicates with a small remote using an nRF8001 Bluetooth connectivity IC and for added safety has a belt clip and a stop button.

Does it work? See for yourself in the video below. We’re sure [Andrew] and his wife will continue to be fit for a long time to come.

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Sailboat Throws Motor Overboard, Adds Sensor Array

For those not familiar with sailing, it might seem like an obsolete way to get around on the water. This isn’t 1492 anymore, and it’s pretty easy to go out and get a boat with a motor to get where you need to go. Sailboats, however, are still one of the most efficient ways to travel. There are essentially no fuel costs, and maintenance on them is often easier than on a boat with an engine. Not to mention the fun involved in flying a hull on a catamaran. Anyway, if you’re [gwilken], you can bring your sailboat even further into modern times by building your own sensor array for it.

The ultimate goal of this project was to get all gauges and sensors reporting data to an iPad, rather than to random gauge clusters around the ship. This includes environmental conditions, speed, and motor status (most larger sailboats have a motor for getting around the marina). A Raspberry Pi ties it all together, including a GPS antenna for monitoring location. [gwilken] also includes a WiFi antenna and a cell antenna for maintaining a network connection for reporting all of this information. With this connectivity, he can also control some functions of the boat as well.

[gwilken] made the decision to ditch the conventional gas motor for a more energy-efficient electric motor. This also has the perk of being essentially maintenance-free, and can even charge his battery in regen mode while his boat is under sail. The sailboat is now fully equipped for the 21st century, in a similar way to another boat’s gauge cluster that was recently featured.

Electric LEGO Longboard Now Complete with Epic Road Test

We recently posted about [James Bruton]’s most excellent oversized LEGO electric longboard. Well, now he has completed the project by tidying a few things and building oversized versions of classic light-up bricks to serve as headlamps and the tail light. Most importantly, he’s hitting the road with it!

He built a LEGO-looking enclosure for the battery as well, based on a 2×6 brick. The battery pack sits behind the motor with the tail light on top and holds the radio control receiver as well the twin LiPos. The head and tail lights pack 24-LED discs and are controlled by [James]’ FS-GT2B 3-channel RC transmitter. Its third channel is just a button, and he can trip that button to activate the lights with the help of a Turnigy receiver-controlled switch.

For an added touch he printed some LEGO flowers and a minifig, suitably oversized, and took the skateboard on the road. The thing has some zip! [James] kept his balance while holding the controller in one hand and a selfie stick with the other. The headlamp housings fell off, and a while later the minifig fell off. Fortunately [James] was able to snap them back into place, in proper LEGO fashion.

[James] runs XRobots and also served as a judge for the 2016 Hackaday Prize. We wrote up his Star Wars builds a while back, as well as his tutorial on mixed reality filming without a green screen.

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