Supercap-Based Cell Phone Charger

November 2, 2013 by 56 Comments

Screen Shot 2013-11-02 at 11.21.58 AM[Barry] sent us a tip about a video from [electronupdate], describing an experimental cell phone charger. It’s a familiar issue: Your cell phone battery is low, and you aren’t in a position to plug it in for hours to charge. Some phones, including the one in his video, have swappable batteries, but that isn’t always an option either. As he explains in the video, a wall outlet can deliver the joule capacity of a high-end battery in a matter of seconds, but it is impossible to charge a battery that quickly. Capacitors, on the other hand, charge near-instantly.

[electronupdate] decided to look at the possibility of using super capacitors to power a typical usb plug. It would allow you to charge a secondary power supply in a short period of time, and then get on your way, letting your phone charge slowly from the device.

His experiment wasn’t entirely successful, possibly because he used 2.7V capacitors, which required a boost regulator and limited the useful voltage range. We think he might have had better success using 120V capacitors and a switching power supply, but it would be nice to see the various options compared.

Oh, [electronupdate] describes using this circuit as you are rushing to your airplane. We aren’t convinced carrying a couple super capacitors through a TSA checkpoint would be the best idea… YMMV.

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Raspberry Pi Becomes A Universal Translator

November 2, 2013 by 59 Comments

hola-me-nombre-david-conroy

We’re still about 150 years away from the invention of the universal translator by [Lt Cdr Sato] of the Enterprise NX-01, but [Dave] has something that’s almost as good: a speech recognition, translation, and text to speech setup for the Raspberry Pi that theoretically allows anyone to speak in sixty different languages.

After setting up all the Linux audio cruft, [Dave] digs in and starts on converting the guttural vocalizations of a meat speaker into something Google’s speech to text service can understand. From there, it’s off to Google again, this time converting text in one language into the writings of another.

[Dave]’s end result is a shell script that works reasonably well for something that won’t be invented for another 150 years. The video below shows the script successfully translating English to spanish, but it should work equally well with other languages such as dutch and latin, as well as less popular language such as esperanto and french.

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Adorable Homebrew Waveform Generator

November 2, 2013 by 25 Comments

waveform

For want of new test equipment, or simply a project, [Enzo] decided he would take a shot at creating his own waveform generator*. Not only is it a great project, it’s also a decent piece of test equipment, with proper signal conditioning, a nice front panel, and a built-in wall transformer.

The guts of [Enzo]’s waveform generator is an AD9833 programmable waveform generator, a neat little chip that can output square and triangle waves fro 0.1 Hz to 3.2 MHz and sine waves from 0.1 Hz to 1.6 MHz. [Enzo] is controlling this chip with a PIC16 microcontroller, with a whole bunch of analog circuitry between the digital domain and the BNC connector on the front panel.

The waveform generator is controlled by a suite of dials and switches on the front panel, giving [Enzo] complete control over his new tool.

* Here’s a Google translation, but good luck with that. Just… get Chrome or something.

Perfect PCBs With An Inkjet Printer

November 2, 2013 by 69 Comments

Instead of mucking about fabbing PCBs with the toner transfer method, or making masks for photosensitive boards, the holy grail of at-home circuit board manufacturing is a direct inkjet-to-etch method. [Don] isn’t quite there yet, but his method of producing circuit boards at home is one of the easiest we’ve ever seen.

[Don]’s boards begin by taking the output from Eagle and printing them with an Epson Artisan 50 inkjet printer. By sticking a piece of cardstock in the printer before the copper board, he’s able to precisely align the traces and pads onto the copper board.

When the board comes out of the printer, it’s only covered in ink. While some specialty inks are enough of an etch resist, [Don] comes up with a clever way to make sure acid doesn’t eat away copper in the needed places – he simply dusts on toner from a copier or laser printer, blows off the excess, and bakes the entire board in a toaster oven.

The result, seen above, are perfect traces on a circuit board without the need for ironing sheets of photo paper onto copper boards.

As far as the, “why didn’t someone think of this sooner” ideas go, this one is at the top. [Don] says the method should work  on sheets of aluminum for printing solder paste masks. Impressive work, and now the only thing left to do is getting two-layer boards down pat. For more direct to copper printing check out the hacks we’ve covered in years past.

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A Nightmare On CNC Street

November 2, 2013 by 43 Comments

[James Dressman] emailed us about his two-year journey of getting a large CNC machine running in his home. He doesn’t currently have a webpage, however his story was so incredible that we just had to feature it.   [James] started by doing plenty of research online, and ordering a new CNC. The real fun started when he opened up a wall to fit the 2300 pound monster into his home. [James] found so much insect and water damage that he ended up rebuilding the entire rear half of his home.

Once the CNC was safely set up, the fun still wasn’t over. Not all family members are keen on having an industrial machine tool in the house. In [James’] case it was the smell of way oil that drove his wife nuts. This was all before spindle problems with the tool itself began to rear their ugly head. Illness and family tragedy put everything on hold for several months, however once [James] strength returned, he attacked the problems with renewed vigor. It was a long and winding road, but he now has a fully functional CNC.

But don’t just take our word for it. Continue after the break to see his photo album and to hear James tell the story in his own words.

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Arduino Keypad Door Automation

November 1, 2013 by 45 Comments

arduino door pad

[Andrea] just sent us this great student hack he made for his room. He’s constructed an Arduino keypad door lock — without using any proper fastening hardware!

The entire build is made out of scrap parts he had lying around: some DVD’s, a bit of wood, an allen key, a motor and belt from a broken printer, an old hard drive enclosure, and a few power supplies. As you can see the entire setup is held up rather artistically using good old duct tape.

The system auto-locks after 5 seconds, and just in case, [Andrea] has hard-coded in a few safety codes into the firmware to allow him to forcefully open the door — you know, if it malfunctions or something. Not overly confident in his code, he also has it reset every 5 minutes of idling to safeguard against potential memory leaks — probably a good idea! All in all it’s a very cool build, and we have to give him props for not damaging the door to mount it! Down the road he’s also planning on adding a knock sensor using the small speaker that is already part of the circuit, because, why not?

Stick around after the break to see this magnificent contraption that would make Red Green proud.

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