Playing Pong With Micro:bits!

April 30, 2018 by James Hobson No comments

Where would the world be today without Pong, perhaps a lot less fun? For people like [Linker3000] the game is an inspiration toward teaching the next generation of hackers to build and play their own version using Micro:bits as controllers!

Aiming for doing all manner of diligence, [Linker3000] says the code can simply be uploaded to an Arduino — foregoing throwing together a circuit of your own — if you want to jump right into things. For the workshop environment, this setup uses composite video outputs — but this shouldn’t be an issue as most TVs still retain these inputs.

Once built — or sketch uploaded — the Micro:bit paddles can be connected to the ATmega328p and played like an old-school controller, but [Linker3000] has enabled Bluetooth control of the paddles’ A and B buttons via the Bitty app. Additionally — if wires really aren’t your thing and Bluetooth is too new-school for such an old game — a second Micro:bit can control the wired paddle using their built-in radio, provided they’re configured accordingly.

On top of Pong, there are also squash and soccer game modes! Check out the demo after the break.

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How To Put The ‘Pro’ In Prototype

April 29, 2018 by Kristina Panos 5 Comments

It’s easy to get professional-quality finishes on your prints and prototypes if you take the right steps. In the final installment of his series about building with Bondo, product designer [Eric Strebel] shows us how it’s done no matter what the substrate.

How does he get such a smooth surface? A few key steps make all the difference. First, he always uses a sanding block of some kind, even if he’s just wrapping sandpaper around a tongue depressor. For instance, his phone holder has a round indent on each side. We love that [Eric] made a custom sanding block by making a negative of the indent with—you guessed it—more Bondo and a piece of PVC. The other key is spraying light coats of both primer and paint in focused, sweeping motions to allow the layers to build up.

If you need to get the kind of surface that rivals a baby’s behind, don’t expect to prime once, paint once, and be done with it. You must seek and destroy all imperfections. [Eric] likes to smooth them over with spot putty and then wet sand the piece back to smooth before applying more primer. Then it’s just rinse and repeat with higher grits until satisfied.

There’s more than one way to smooth a print, of course. Just a few weeks ago, our own [Donald Papp] went in-depth on the use of UV resin.

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An Open-Source Turbomolecular Pump Controller

April 28, 2018 by Jenny List 18 Comments

It’s not every project write-up that opens with a sentence like “I had this TURBOVAC 50 turbomolecular pump laying around…”, but then again not every write-up comes from someone with a lab as stuffed full of goodies as that of [Niklas Fauth]. His pump had an expired controller board, so he’s created an open-source controller of his own centred upon an STM32. Intriguingly he mentions its potential use as “I want to do more stuff with sputtering and Ion implantation in the future“, as one does of course.

So given that probably not many Hackaday readers have a turbomolecular pump lying around but quite a few of you will find the subject interesting, what does this project do? Sadly it’s a little more mundane than the pump itself, since a turbomolecular pump is a highly specialised multi-stage turbine, this is a 3-phase motor controller with analogue speed feedback taken from the voltage across a couple of the motor phases. For this reason he makes the point that it’s a fork of his hoverboard motor controller software, the fruits of which we’ve shown you in the past. There isn’t a cut-out timer should the motor not reach full speed in a safe time, but he provides advice as to where to look in the code should that be necessary.

This is by no means the first turbomolecular pump to make it to these pages, in 2016 we brought you one taking inspiration from a Tesla turbine.

An Open Source Sip-and-Puff Mouse For Affordable Accessibility

April 27, 2018 by Dan Maloney 22 Comments

At the core of any assistive technology is finding a way to do something with whatever abilities the user has available. This can be especially difficult in the case of quadriplegia sufferers, the loss of control of upper and lower limbs caused by spinal cord damage in the cervical region. Quadriplegics can gain some control of their world with a “Sip-and-puff” device, which give the user control via blowing or sucking on a mouthpiece.

A sip-and-puff can make a world of difference to a quadriplegic, but they’re not exactly cheap. So to help out a friend, [Jfieldcap] designed and built an open source sip-and-puff mouse on the cheap. As is best for such devices, the design is simple and robust. The hollow 3D-printed mouthpiece acts as handle for a joystick module , and a length of tubing connects the mouthpiece to a pressure sensor. An Arduino lets the user move his head to position the cursor; hard sips and puffs are interpreted as left and right clicks, while soft mouth pressure is used for scrolling. In conjunction with some of the accessibility tools in modern OSes and personal assistant software like Siri or Cortana, the sip-and-puff opens up the online world, and for all of $50 in material.

We’re impressed by the effort and the results, but we worry that the standard PLA used for the mouthpiece won’t stand up to the cleaning it’ll need. Of course, printing extra mouthpieces is easy, but since it’s going to be in contact with the mouth, perhaps a review of food-safe 3D-printing is in order.

Cams And Pushrods Improve 3D-Printed Compressed Air Engine

April 27, 2018 by Dan Maloney 12 Comments

Some folks just can’t leave well enough alone, and that often ends up being a good thing. Such is the case with this 3D-printed compressed air engine, which just keeps getting better.

The design has changed a lot since we first covered [Tom Stanton]’s attempts at reviving the powerplant from the glory days of the Air Hogs line of toys, which he subsequently built a plane around. The engine was simple, with a ball valve that admitted air into the cylinder when a spring mounted to the top of the piston popped it out of the way. That spring has always bothered [Tom], though, compelling him to go back to the drawing board. He wanted to replace the ball valve with one actuated by a cam and pushrod. This would increase the complexity of the engine quite a bit, but with the benefit of eliminating the fail point of the spring. With a few iterations in the design, he was able to relocate the ball valve, add a cam to the crankshaft, and use a pushrod to open the valve. The new design works much better than the previous version, sounding more like a lawnmower than a 3D-printed engine should. Check out the design process and some tests in the video below.

And speaking of lawnmowers that run on compressed air…

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A Low Cost, Dead Tree Touch Screen

April 27, 2018 by Dan Maloney 38 Comments

Remember the “paperless office”? Neither do we, because despite the hype of end-to-end digital documents, it never really happened. The workplace is still a death-trap for trees, and with good reason: paper is cheap, literally growing on trees, and it’s the quickest and easiest medium for universal communication and collaboration. Trouble is, once you’re done scribbling your notes on a legal pad or designing the Next Big Thing on a napkin, what do you do with it?

If you’re anything like us, the answer to that question is misplacing or destroying the paper before getting a chance to procrastinate transcribing it into some useful digital form. Wouldn’t paper that automatically digitizes what you draw or write on it be so much better? That’s where this low-cost touch-sensitive paper (PDF link) is headed, and it looks like it has a lot of promise. Carnegie-Mellon researchers [Chris Harrison] and [Yang Zhang] have come up with cheap and easy methods of applying conductive elements to sheets of ordinary paper, and importantly, the methods can scale well to the paper mill to take advantage of economies of scale at the point of production. Based on silk-screened conductive paints, the digitizer uses electrical field tomography to locate touches and quantify their pressure through a connected microcontroller. The video below shows a prototype in action.

Current cost is 30 cents a sheet, and if it can be made even cheaper, the potential applications range from interactive educational worksheets to IoT newspapers. And maybe if it gets really cheap, you can make a touch-sensitive paper airplane when you’re done with it.

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Turn Failed Prints Into Office Fun With A Paper Airplane Maker

April 26, 2018 by Dan Maloney 11 Comments

If you’re anything like us, you feel slightly guilty when you send a job to a printer only to find that twenty pages have printed wrong. Maybe it’s a typo, maybe it’s the dreaded landscape versus portrait issue. Whatever it is, trees died for your mistake, and there’s nothing you can do about it except to recycle the waste. But first, wipe that guilt away by using this one-stroke paper airplane maker to equip the whole office for an epic air battle.

We have to admit, automated paper handling has always fascinated us. The idea that a printer can reliably (sometimes) feed individual sheets of a stack is a testament to good design, and don’t even get us started about automatic paper folding. [Jerry de Vos]’ paper airplane maker doesn’t drive the sheets through the folder — that’s up to the user. But the laser-cut plywood jig does all the dirty work of creating a paper airplane. The sheet is clipped to an arm that pulls the paper through a series of ramps and slots that force the paper gently into the five folds needed for the classic paper dart. It’s fascinating to watch, and even though everyone seems to be using it very gingerly lest the paper tear, we can see how adding some rollers and motors from a scrapped printer could entirely automate the process. Think of the fun a ream of paper could provide around the office then.

Oh, wait…

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