So, You’ve Never Made A Spaceframe Before

It is sometimes a surprise in our community of tinkerers, builders, hackers, and makers, to find that there are other communities doing very similar things to us within their own confines, but in isolation to ours. A good example are the modified vehicle crowd. In their world there are some epic build stories and the skills and tools they take for granted would not in any way be unfamiliar to most Hackaday readers.

As part of a discussion about electric vehicles near where this is being written, someone tossed an interesting link from that quarter into the mix; a two-part treatise on building ultra-light-weight tubular frame vehicles. Or space frames, as you might know them.

You might think that making a tubular framed for a vehicle would be a straightforward enough process, but as the article explains, it contains within it a huge well of geometry and metallurgy to avoid a creation that is neither too heavy nor contains excessive weakness. Part one deals mainly with prototyping a frame, the selection of materials and joining tubes, while part two goes into more detail on fabrication. The author likes brazing which may offend the sensibilities of welding enthusiasts, but you can substitute your jointing tech of choice.

A particularly neat suggestion, one of those simple ideas that make you wish you’d thought of it yourself, is to prototype a frame in miniature with copper wire and solder to evaluate the effect of different forces upon it before you commit your final design to steel.

The articles are a few years old, but no less pertinent in the information they contain. Meanwhile if you are a spaceframe veteran, then you may have your own suggestions for the comments below. And if you’d like some tips on how not to build a spaceframe, have a look at this motorcycle.

Thank you [JHR] and [Jarkman] for the tips.

Electric Longboard with All-New Everything

We love [lolomolo]’s Open Source electric longboard project. Why? Because he completely re-engineered everything while working on the project all through college. He tackled each challenge, be it electronic or mechanical as it came, and ended up making everything himself.

The 48″ x 13″ deck is a rather unique construction utilizing carbon fiber and Baltic birch. In testing the deck, [lolomol] found the deflection was less than an inch with 500 lbs. on the other end. He modified the Caliber II trucks to add four 2250W Turnigy Aerodrive brushless outrunners driving the wheels with the help of belts. The motors are controlled by VESC, an Open Source speed controller. There are a lot of fun details, like the A123 lithium cells equipped with custom battery management system PCBs.

The board sports 5W RGBW headlights that are so bright he can only run them at 10% PWM, plus RGB LED underlighting. All of it is controlled by an onboard Linux box. You can check out [lolomolo]’s GitHub repository for code, schematics, and CAD files. His Instructable for this project also has more design notes and thoughts.

If sweet longboards are your bag, check out the 3D-printed longboard and the long-distance electric longboard we published previously.

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.

Continue reading “Hackaday Prize Entry: Powered Running Stroller Keeps You Running”