DIY Falcon Heavy 2nd stage test flight of BPS.space

Rocket Science With The Other SpaceX

September 18, 2018 by 29 Comments

When you say that something’s not rocket science you mean that it’s not as hard to understand or do as it may seem. The implication is that rocket science is something which is hard and best left to the likes of SpaceX or NASA. But that’s not the hacker spirit.

Rocket science with BPS.Space[Joe Barnard] recently had an unsuccessful flight of his Falcon Heavy’s second stage and gives a very clear explanation of what went wrong using those two simple concepts along with the thrust, which in this case is just the force applied to the moment arm.

And no, you didn’t miss a big happening with SpaceX. His Falcon Heavy is a homebrew one using model rocket solid boosters. Mind you, it is a little more advanced than that as he’s implemented thrust vectoring by controlling the engine’s direction using servo motors.

And therein lies the problem. The second stage’s inertia is so small and the moment arm so short that even a small misalignment in the thrust vectoring results in a big effect on the moment arm causing the vehicle to deviate from the desired path. You can see this in the first video below. Another issue he discusses is the high drag, but we’ll leave that to the second video below which contains his explanation and some chart analysis.

So yeah, maybe rocket science is rocket science. But there’s no better way to get your feet wet then to get out there and get building.

Continue reading “Rocket Science With The Other SpaceX” →

ARM-Based NAS Is A Low Cost, Low Power Beauty

September 18, 2018 by 40 Comments

A NAS is always a handy addition to a home network, but they can be a little pricey. [Blake Burkhart] decided to create his own, prioritising budget and low power considerations, with a secondary objective to produce some router and IoT functionality on the side.

A Banana Pi R2 was a good choice to meet these requirements, being a router-based development board that also sports dual SATA connectors and gigabit Ethernet. [Blake] had some retrospective regrets about the performance of this particular SBC, but it does just fine when functioning purely as a NAS.

The enclosure for the device is a three bay hot-swap HDD module, with one of the bays gutted and used for the Banana Pi. It’s a simple idea, elegantly executed, which looks great. To access the ports of the Banana Pi, a custom acrylic side panel was laser cut, which also allowed LEDs to shine through – obligatory for any DIY server/computer build. When mounting this panel to the existing enclosure, [Blake] was reluctant to take his chances tapping the brittle acrylic, instead opting to melt the threads into the plastic with a pre-torched screw. We find that tapping acrylic is usually okay if you take it slow, but heat-tapping does sound fun.

The 12 V fan that came built into the hot-swap enclosure was too loud and awkwardly came in a non-standard size with a non-standard connector. What’s more, a buzzer alarm was triggered any time the fan was disconnected and 0 RPM was detected. [Blake]’s solution was to rewire the power pin of the connector to a 5 V rail; he found that running the fan at 5 V led to much quieter performance whilst keeping the HDDs sufficiently cool.

We find that when it comes to DIY network gear and routers, there are two approaches. Either create your own bespoke solution that perfectly fits your needs, like this perfect home router, or work around your current gear and build some tech to automatically reboot it for you.

 

It’s The Web, Basically

September 17, 2018 by 43 Comments

If you are of a certain age, you probably learned to program in Basic. Even if you aren’t, a lot of microcontroller hobbyists got started on the Basic Stamp, and there are plenty of other places where to venerable language still hides out. But if you want to write cool browser applications, you have to write JavaScript, right? Google will now let you code your web pages in Basic. Known as WWWBasic, this is — of course — a Javascript hack that you can load remotely into a web page and then have your page use Basic for customization. You can even import the thing into Node.js and use Basic inside your JavaScript, although it is hard to think of why you’d want to.

According to the project’s documentation — which is pretty sparse so far, we’re afraid — the Basic program is compiled into JavaScript on page load. There are a few examples, so you can generally pick up what’s available to use. There are graphics, the ability to read a keyboard key, and a way to handle the mouse.

Continue reading “It’s The Web, Basically” →

A $1, Linux-Capable, Hand-Solderable Processor

September 17, 2018 by 87 Comments

Over on the EEVblog, someone noticed an interesting chip that’s been apparently flying under our radar for a while. This is an ARM processor capable of running Linux. It’s hand-solderable in a TQFP package, has a built-in Mali GPU, support for a touch panel, and has support for 512MB of DDR3. If you do it right, this will get you into the territory of a BeagleBone or a Raspberry Pi Zero, on a board that’s whatever form factor you can imagine. Here’s the best part: you can get this part for $1 USD in large-ish quantities. A cursory glance at the usual online retailers tells me you can get this part in quantity one for under $3. This is interesting, to say the least.

The chip in question, the Allwinner A13, is a 1GHz ARM Cortex-A8 processor. While it’s not much, it is a chip that can run Linux in a hand-solderable package. There is no HDMI support, you’ll need to add some more chips (that are probably in a BGA package), but, hey, it’s only a dollar.

If you’d like to prototype with this chip, the best options right now are a few boards from Olimex, and a System on Module from the same company. That SoM is an interesting bit of kit, allowing anyone to connect a power supply, load an SD card, and get this chip doing something.

Currently, there aren’t really any good solutions for a cheap Linux system you can build at home, with hand-solderable chips. Yes, you could put Linux on an ATMega, but that’s the worst PC ever. A better option is the Octavo OSD335x SoC, better known as ‘the BeagleBone on a Chip’. This is a BGA chip, but the layout isn’t too bad, and it can be assembled using a $12 toaster oven. The problem with this chip is the price; at quantity 1000, it’s a $25 chip. At quantity one, it’s a $40 chip. NXP’s i.MX6 chips have great software support, but they’re $30 chips, and you’ll need some DDR to make it do something useful, and that doesn’t even touch the fiddlyness of a 600-ball package

While the Allwinner A13 beats all the other options on price and solderability, it should be noted that like all of these random Linux-capable SoCs, the software is a mess. There is a reason those ‘Raspberry Pi killers’ haven’t yet killed the Raspberry Pi, and it’s because the Allwinner chips don’t have documentation and let’s repeat that for emphasis: the software is a mess.

Still, if you’re looking for a cheap chip you can solder at home, this one seems to be the only game in town. We’re really looking forward to seeing what you make with it!

Hacked Electric Toothbrush Defeats Locks With Ease

September 17, 2018 by 41 Comments

The movie version of lockpicking tends to emphasize the meticulous, delicate image of the craft. The hero or villain takes out a slim wallet of fine tools, applies them with skill and precision, and quickly defeats the lock. They make it look easy, and while the image isn’t far from reality, there are other ways to pick a lock.

This expedient electric toothbrush lockpick is a surprisingly effective example of the more brute force approach to lockpicking. As [Jolly Peanut] explains, pin tumbler locks work by lining up each pin with the shear line of the cylinder, which allows the lock to turn. This can be accomplished a pin at a time with picks, or en masse by vibrating the pins until they randomly line up with the shear line just long enough for the lock to turn. A locksmith might use a purpose-built tool for the job, but a simple battery-powered electric toothbrush works in a pinch too. [Jolly Peanut] removed the usual business end of the brush to reveal a metal drive rod that vibrates at a high frequency. The rod was slimmed down by a little grinding to fit into the keyway of a lock, and with the application of a little torque, the vibration is enough to pop the pins into the right position. He tries it out on several locks in the video below, and it only takes a few seconds each time.

Such brute force methods have their drawbacks, of course. They’re not exactly subtle, and the noise they create may attract unwanted attention. In that case, hone your manual lockpicking skills with a giant 3D-printed see-through lock.

Continue reading “Hacked Electric Toothbrush Defeats Locks With Ease” →

Open Source Paramotor Using Quadcopter Tech

September 17, 2018 by 24 Comments

Have you ever dreamed of flying, but lack the funds to buy your own airplane, the time to learn, or the whole hangar and airstrip thing? The answer might be in a class of ultralight aircraft called powered paragliders, which consist of a soft inflatable wing and a motor on your back. As you may have guessed, the motor is known as a paramotor, and it’s probably one of the simplest powered aircraft in existence. Usually little more than big propeller, a handheld throttle, and a gas engine.

But not always. The OpenPPG project aims to create a low-cost paramotor with electronics and motors intended for heavyweight multicopters. It provides thrust comparable to gas paramotors for 20 to 40 minutes of flight time, all while being cheaper and easier to maintain. The whole project is open source, so if you don’t want to buy one of their kits or assembled versions, you’re free to use and remix the design into a personal aircraft of your own creation.

It’s still going to cost for a few thousand USD to get a complete paraglider going, but at least you won’t need to pay hangar fees. Thanks to the design which utilizes carbon fiber plates and some clever hinges, the whole thing folds up into a easier to transport and store shape than traditional paramotors with one large propeller. Plus it doesn’t hurt that it looks a lot cooler.

Not only are the motors and speed controls borrowed from the world of quadcopters, but so is the physical layout. A traditional paramotor suffers from a torque issue, as the big propeller wants to twist the motor (and the human daring enough to strap it to his or her back) in the opposite direction. This effect is compensated for in traditional gas-powered paramotor by doing things like mounting the motor at an angle to produce an offset thrust. But like a quadcopter the OpenPPG uses counter-rotating propellers which counteract each others thrust, removing the torque placed on the pilot and simplifying design of the paraglider as a whole.

If you still insist on the fixed-wing experience, you could always get some foam board and hope for the best.

[Thanks to Luke for the tip.]

Continue reading “Open Source Paramotor Using Quadcopter Tech” →

Man’s Best Robotic Friend

September 17, 2018 by 4 Comments

When it comes to robotics, some of the most interesting work — and certainly the most hilarious — has come from Boston Dynamics, and their team of interns kicking robotic dogs over. It’s an impressive feat of engineering, and even if these robotic pack mules are far too loud for their intended use on the battlefield, it’s a great showcase of how cool a bunch of motors can actually be.

It’s not quite up there with the Boston Dynamics robots, but [Dimitris]’ project for the Hackaday Prize is an almost equally impressive assemblage of motors, 3D printed parts, SLAM processing and inverse kinematics. I suppose you could also kick it over and watch it struggle for laughs, too.

This robotic dog was first modeled in Fusion 360, and was designed with  22 Dynamixel AX-12A robot actuators: big, beefy, serial-controllable servos. Of course, bolting a bunch of motors to a frame is the easy part. The real challenge here is figuring out the kinematics and teaching this robot dog how to walk. This is still a work in progress, but so far [Dimitris] is able to move the spine, keep the feet level with the ground, and have the robot walk a little bit. There’s still work to do, but there’s an incredible amount of work that’s already been done.

The upcoming features for this robot include a RealSense camera mounted on the head for 3D visualization of the surroundings. There’s also plans for a tail, loosely based on some of the tentacle robots we’ve seen. It’s going to be a great project when it’s done, and it’s already an excellent entry for the Hackaday Prize.

Continue reading “Man’s Best Robotic Friend” →