3D Printed… Measuring Tape?

March 25, 2014 by James Hobson 41 Comments

3d printed measuring tape

Here’s a new one to push the envelope… How about a 3D printed measuring tape?

This unique 3D printed tool was designed and printed in a single job. [Angry Monk] has been challenging himself lately with these intricate designs, having recently finished a completely 3D printed set of dial calipers, which is impressive in its own right.

Looking for his latest challenge he pondered what it would take to make this 3D printed tape measure. As he continued to think about it he realized how complex it would actually be to pull off. After designing and printing a few of the basic parts to help him solidify his ideas, he set to work. This tape measure has 114 individual parts. It includes 52″ of tape links with 1″ divisions and markings down to the 1/8th of an inch. It even features a hand crank (sorry no spring return) to roll up the tape.

Now as you can imagine, a complex assembly like this is a bit out of the realm of possibility for regular hobby 3D printers — a UV resin printer might be able to do it, but [Angry Monk] used a commercial Objet Eden 3D printer. Still though — it’s an impressive display of design, check out the following video and see for yourself.

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First Stab At Motion Sensor To Disconnect A Car Charger

March 24, 2014 by Mike Szczys 108 Comments

motion-sensing-car-charger

[Pixel] just sent in this automotive hack which disconnects his car charger when the vehicle stops moving for at least 10 minutes. Why would you need such a thing? The 12V outlet in his vehicle isn’t disconnected when the ignition is turned off. If he leaves a charger plugged in when parking the car, he often returns to a drained battery.

The fritzing diagram tells the story of this hack. He’s using a 7805 to power the Arduino mini. This monitors an ADXL362 accelerometer, starting the countdown when motion is no longer sensed by that chip. At the 10-minute mark the N-channel MOSFET kills the ground side of the outlet. Good for [Pixel] for including a resetable fuse on the hot side. But it was the diode all the way to the left that caught our eye. Turns out this is part of a filtering circuit recommended in a forum post. It’s a Zener that serves as a Transient-Voltage-Suppression diode.

Another comment on that thread brings up the issue we also noticed. The 7805 linear regulator is constantly powered. Do you think putting the uC into sleep and leaving the linear regulator connected is an adequate solution? If not, what would you do differently?

Bookworm Playing Bot Tests Programmer’s OCR Skills

March 24, 2014 by Mike Szczys 9 Comments

bookworm-bot

Check out this brainy bot with [Jari] whipped up to dominate the Bookworm Deluxe scoreboard. The bot runs on top of a win32 machine, pulling screenshots to see the game board and simulating mouse clicks to play. The video after the jump shows that it plays like a champ, but it took some doing to get this far and [Jari] took the time to share all of the development details.

The hardest part of writing these types of bots is recognizing the game pieces. Check out all of the animation that’s going on in the still shot above… a lot of the tiles are obscured, there are different colors, and the tiles themselves shift as the bot spells and submits each word.

After some trial and error [Jari] settled on an image pre-processor which multiplies pixel values by themselves four times, then looks at each pixel with a 1/6 threshold to produce a black and white face for each tile. From there a bit of Optical Character Recognition compares each tile to a set of known examples. This works remarkably well, leading into the logic and dictionary part of the programming challenge.

Do you think this was easier or harder than the Bejeweled Blitz bot. That one was looking for specific pixel regions, this one is basically a focused roll-your-own OCR script.

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Rebuilding A 50,000 Volt Power Supply

March 24, 2014 by Brian Benchoff 43 Comments

Spark

The theory behind building power supplies is relatively easy, but putting it into practice and building a multi-kilovolt supply is hard. A big transformer in air will simply spark to itself, turning what could be something very cool into something you just don’t want to be around. [glasslinger] over on YouTube is an expert at this sort of thing, as shown in his 50,000 Volt power supply build. That’s a 55 minute long video, and trust us: it’s worth every minute of your time.

[glasslinger] began his build by taking an old 15,000 Volt neon sign transformer and repurposing the coils and cores for his gigantic 50,000 volt transformer. There was a small problem with this little bit of recycling: the neon sign transformer was potted with tar that needed to be removed.

To de-pot the transformer, [glasslinger] made a small oven from a helium tank, melting all the goo out with an old school gasoline torch. From there, hours and hours of cleaning ensued.

The transformer cores were cleaned up and cut down, and a new primary wound. A small-scale test (shown above) using the old secondaries resulted in a proof of concept with some very large sparks. The next step was putting the entire transformer in a box and filling it with transformer oil.

The money shot for this build comes when [glasslinger] assembles his transformer, rectifier, and all the other electronics into a single, surprisingly compact unit and turns standard wall power into a 50,000 Volt spark. You can literally smell the ozone from the video.

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Soft Robotics, Silicone Rubber, And Amazing Castings

March 24, 2014 by Brian Benchoff 13 Comments

Most of the robotics projects we see around here are heavy, metallic machines that move with exacting precision with steppers, servos, motors, and electronics. [Matthew] is another breed of roboticist, and created a quadruped robot with no hard moving parts.

[Matthew] calls his creation the Glaucus, after the blue sea slug Glaucus atlanticus. Inside this silicone rubber blob are a series of voids, allowing compressed air to expand the legs, gently inching Glaucus across a table under manual or automatic control.

Even though no one seems to do it, making a few molds for casting on a 3D printer is actually pretty easy. [Matthew] is taking this technique to an extreme, though: First, a mold for the interior pressure bladders are printed, then a positive of this print made in silicone rubber. These silicone molds – four of them, for the left, right, top and bottom – are then filled with wax, and the wax parts reassembled inside the final ‘body’ mold. It’s an amazing amount of work to make just one of these soft robots, but once the molds and masters are made, [Matthew] can pop out a soft robot every few hours or so.

There’s a lot more info on Glaucus over on the official site for the build, and a somewhat simpler ‘compressed air and silicone rubber’ tentacle [Matthew] built showing off the mechanics. Video below.

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The Gathering: Shanghai’s Hackaday Community

March 24, 2014 by Aleksandar Bradic 10 Comments

It happened! The Gathering crossed the Pacific and landed in Shanghai on Thursday, March 20th. It took place at the venue ironically called ‘Abbey Road’ (it’s the only one we could find on such a short notice) and more than 150 people showed up. The whole scene had a huge Chatsubo feel too it – an eclectic mix of local and expat hackers and engineers, professors, students and all sorts of industry mercenaries from around the world. And everyone with skull-and-wrenches t-shirt or a sticker on.

I can only imagine what Chinese police would think if they happened to drop by. Not to mention if they asked how in the world did all these ‘anarchist’ t-shirts enter the country.

But that’s another story…

We met a lot of exciting people and heard all sorts of weird tales, such as the (off-the-record) one about the real reasons behind certain well-known laptop manufacturer’s batteries bursting into flames. We also got a lot of great advice on smuggling electronic components out of China and other everyday tips & tricks.

My favorite conversation was with [Alexander Klink] on his research in Denial of Service attacks using algorithmic complexity of collision resolution in (a priori known) hash functions. Though the original paper is more than two years old, its takeaways can still have a huge impact on all sorts of software and hardware devices out there.

The general theme of the night was how exciting it is to live in a place like Shanghai, where rapid urban growth and access to manufacturing resources meets a blossoming technology and art scene. It is even more so thanks to places like Xin Che Jian, which make being a “hacker” a socially acceptable thing on the other side of the Great Firewall.

That said, reading all of Hackaday content still requires a proxy.

3 Cheap Hood/Hatchback/Topper Mods To Save Your Noggin

March 24, 2014 by Todd Harrison 32 Comments

This is a mod more than a hack but any time you can alter original equipment to maintain its usability is a win-win scenario for you and the environment. Everyone has or knows somebody that has a vehicle and most vehicles nowadays have some type of hatchback or hood where the support solution is gas filled struts. Inevitably these gas filled struts fail with age and the failure is accelerated in hotter or colder climates. If you ever had to replace these items you know they can cost a minimum of $20 to as much as $60 a piece. Most vehicles require two, four or even eight of these costly little devices.

[Brian] from Briansmobile1 YouTube channel documented three simple and low cost solutions. We all probably know of the vice clamp solution but that is cumbersome and still an expensive solution which is not always very handy or fast. Another solution is to cut a piece of rubber hose in a kind of special way so it is easy to put on and take off the shaft and dangles from a string so it’s always available. The best solution was to use a hitch pin also connected to a string or wire. To make the hitch pin work you have to grind a couple of notches on either side of the lift shaft at just the right spot so the pin can be snapped on and prevent the shaft from retracting at your selected height.

We are sure these solutions will come in handy at some time in most everyone’s driving career. Just after the break we will link to all three of [Brian’s] handy videos on gas strut fix solutions. And if you do your own automotive repair we can definitely recommend [Brian’s] channel of over 600 vehicle repair and maintenance videos which normally come with a dose of philosophy and humor.

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