Slimline USB Charger For Tiny Ham Radios

September 5, 2015 by Dan Maloney 12 Comments

The recent trend to smaller and smaller handy talkie (HT) transceivers is approaching the limits of the human interface. Sure, engineers could probably continue shrinking the Baofeng and Wouxun HTs further, but pretty soon they’ll just be too small to operate. And it’s getting to the point where the accessories, particularly the battery charging trays, are getting bulkier than the radios. With that in mind, [Mads Hobye] decided to slim down his backpacking loadout by designing a slimline USB charger for his Baofeng HT.

Lacking an external charging jack but sporting a 3.7 volt battery pack with exposed charging terminals on the rear, [Mads] cleverly capitalized on the belt clip to apply spring tension to a laser-cut acrylic plate. A pair of bolts makes contact with the charging terminals on the battery pack, and the attached USB cable allows him to connect to an off-the-shelf 3.7 volt LiPo USB charger, easy to come by in multicopter circles. YMMV – the Baofeng UV-5R dual-band HT sitting on my desk has a 7.4 volt battery pack, so I’d have to make some adjustments. But you have to applaud the simplicity of the build and its packability relative to the OEM charging setup.

This isn’t the first time we’ve seen [Mads] on Hackaday. He and the FabLab RUC crew were recently featured with their open-source robotic arm.

Demonstrating Science At Harvard University

September 4, 2015 by Mike Szczys 18 Comments

What if there was a job where you built, serviced, and prepared science demonstrations? This means showing off everything from principles of physics, to electronic theory, to chemistry and biology. Would you grab onto that job with both hands and never let go? That was my reaction when I met [Dan Rosenberg] who is a Science Lecture Demonstrator at Harvard University. He gave me a tour of the Science Center, as well as a behind the scenes look at some of the apparatus he works with and has built.

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Experimental Theater Helps Field Test Haptic Navigation Device

September 4, 2015 by Dan Maloney 7 Comments

The “absorbed device user” meme, like someone following Google Maps on a smart phone so closely that they walk out into traffic, is becoming all too common. Not only can an interface that requires face time be a hazard to your health in traffic, it’s also not particularly useful to the visually impaired. Haptic interfaces can help the sighted and the visually impaired alike, but a smart phone really only has one haptic trick – vibration. But a Yale engineer has developed a 3D printed shape-shifting navigation tool that could be a haptics game changer.

Dubbed the Animotus by inventor [Ad Spiers], the device is a hand-held cube split into two layers. The upper layer can swivel left or right and extend or retract, giving the user both tactile and visual clues as to which direction to walk and how far to the goal. For a field test of the device, [Ad] teamed up with a London theater group in an interactive production of the play “Flatland”, the bulk of which was staged in an old church in total darkness. As you can see in the night-vision video after the break, audience members wearing tracking devices were each given an Animotus to allow them to navigate through the interactive sets. The tracking data indicated users quickly adapted to navigation in the dark while using the Animotus, and some became so attached to their device that they were upset by the ending of the play, which involved its mock confiscation and destruction.

Performing art applications aside, there’s plenty of potential for haptics with more than one degree of freedom. Imagine a Bluetooth interface to the aforementioned Google Maps, or an electronic seeing-eye dog that guides a user around obstacles using an Animotus and a camera. There’s still plenty of utility in traditional haptics, though, as this Hackaday Prize semi-finalist shows.

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Tint Your Epoxy Resin With Toner Powder

September 4, 2015 by Dan Maloney 67 Comments

Epoxy resin is useful stuff. Whether for gluing stuff together or potting components, epoxy is a cheap and versatile polymer that finds its way into many hackish projects. But let’s face it – the stock color of most commercially available epoxies lacks a certain pizzazz. Luckily, [Rupert Hirst] at Tallman Labs shows us that epoxy is easily tinted with toner powder from a laser printer or copier.

Looking for a way to make his epoxy blend into a glue-up, [Rupert] also demonstrates that colored epoxy makes a professional looking potting compound. There’s just something about the silky, liquid look of a blob of cured black epoxy. [Rupert] harvested his toner powder from a depleted printer cartridge; only a smidgen is needed, so you should be able to recover plenty before recycling the cartridge. We’ve got to admit that seeing toner handled without gloves gives us the willies, though. And don’t forget that you can find cyan, magenta and yellow cartridges too if basic black isn’t your thing.

Sometimes it’s better to leave your epoxy somewhat clear, like when you’re potting an LED matrix for a pendant. But this neat trick might just spiff up your next project a bit.

[Thanks, Jake]

How To Build Anything Using Delrin And A Laser Cutter

September 3, 2015 by Sonya Vasquez 58 Comments

Need a simple fab process to go from a humble vector graphic to a final part — in a matter of minutes? The CO₂ laser cutter might be the right choice. As these tools open themselves up to widespread use through hackerspaces, I decided to give Delrin some well-deserved time under the spotlight.

The laser cutter yet-again proves itself a formidable tool with the construction of GameCube-Bot V2

This guide is a brief collection of tips and techniques that I’ve either learned from others or discovered on my own over the last couple years working with laser-cut Delrin (a.k.a Acetal) for functional prototypes. I hope this guide serves you well as we keep exploring the limits of the material.

As a disclaimer, keep in mind that in no way are these techniques unique or limited to Delrin. Many are not only years old but also common practice in either engineering design or the local machine shop. This article simply highlights the techniques shown here that perform both repeatably and predictably with Delrin and a couple hand-tools, and I hope to share them with a growing audience of laser cutter enthusiasts.

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Recycled Factory Recycles Soda Bottles

September 2, 2015 by Dan Maloney 32 Comments

All over the world, mountains of polyethylene terephthalate (PET) plastics are available for recycling in the form of soda bottles. And wherever there is enough cheap raw material, a market is sure to emerge for it. One brilliant inventor in Brazil has decided to capitalize on this market by building a magnificent factory to turn PET bottles into threads, rope, and other products.

Not a word of English is spoken in the video, and our Portuguese stops at obrigado, but you don’t really need to understand what’s being said to know what’s going on. Built from what looks to be the running gear of several bicycles and motors from various cast-off appliances, our nameless genius’ machines slit the PET bottles into fine threads, winds the thread onto spools, and braids the threads into heavier cords. We love the whole home-brew vibe of the machines; especially clever is the hacked desk calculator wired to a microswitch to count revolutions, and the salvaged auto jack used to build a press for forming the broom heads. All in all it’s a pretty amazing little factory cranking out useful products from zero-cost raw material.

We’d love to have more context about what’s being said in the video, so we’ll put this one out there for our Portuguese-speaking readers. Maybe we can get a partial translation in the comments? If so, then obrigado.

[Thanks W4RIS]

Shift Register Powered Realistic Candle Flicker

August 29, 2015 by George Graves 54 Comments

[Kevin Darrah] recently went out to dinner at a restaurant that was using some cheap LED candles (yuck) instead of the real thing. And in the true spirit of a hacker, he started to notice the patterns programmed into the fake flame repeat over and over again. And like any hacker might, his mind started to devise a better way.

Now’s the time where some of us lazy hackers might grab a microcontroller, and copy and paste in some pseudo-random number generating code you found on the Internet, but not [Kevin]. The basics of his hack uses two shift registers tied together that are fed a single clock signal, and also a latch signal that is slightly delayed version of the same signal made by a RC-time circuit.

The randomness of the output is created is by feeding back the outputs of the shift registers to an XOR gate. If you want to learn more about this, the technique it’s called a “linear feedback shift register“. It’s commonly used as a poor-man’s random number generator, although it’s not technically truly random, statistically it does a very good job. You can see the results in the video after the break where [Kevin] describes the circuit. He wraps up the hack with a battery and solar charging circuit as well to make a completed project.

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