Hacklet 85: Alternative Audio Amplifiers

November 21, 2015 by Brian Benchoff 6 Comments

When you think of amplifiers, you’re probably thinking of audio or some big ‘ol power amps for radios. While interesting, there are some very interesting ‘alternative’ amplifiers floating around hackaday.io that are more than just power amps, and exceedingly useful, to boot.

[Ronald] bought an XMS amplifier a few years ago, and although it worked well, every time he changed the input, the loudness had to be toggled. One thing led to another, and he realized this amplifier had a four-channel audio processor that could be controlled by I2C. This was the beginning of his Network Amplifier.

Inside the box is a Raspberry Pi that controls a PT2314-based amplifier. Also included is a 2×16 character LCD, a few LEDs, switches, and a rotary encoder. There was an Android app that controlled the amplifier, but this was discarded for a better looking web-based solution. Now [Ronald] has every audio source available over WiFi.

What if you want an audio amplifier without a speaker? Wait, what? That’s what [DeepSOIC] is doing with his experiments in ion wind loudspeakers.

‘Ion wind lifters’ have been around for decades now, mostly in the labs of slightly off-kilter people who believe this is the technology aliens are using to visit earth. Nevertheless, ion wind lifters produce an airflow, and if you make that wind variable, you get sound. Pretty cool, huh?

The amplifier for this project uses a tube to modulate kilovolt supply through the ion ‘blower’. Does it work? Sure does. [DeepSOIC] got a piece of 0.2 mm nichrome wire to discharge ions into the air, after which the ions drift into the second electrode. The result is sound, and the entire project is built deadbug style. It really doesn’t get cooler than this.

Continuing with the tube amp trend, [Marcel] built the cheapest little tube amp around.

The design of an audio tube amp is fairly simple business. First, you start with a big ‘ol transformer, and rectify the AC into DC. This gets fed into a preamp tube, and this is fed into a bigger power tube.

In about 50 years of development, tube designers had the technology down pat by the mid 1950s, and triode/pentode tubes were created. This allowed tube designers to condense two amplifier stages into a single tube. While this setup was usually used for cheap, toy-like electronics, you can still buy the ECL82 tube today.

[Marcel] took one of these tubes, added a rectifier tube, transformer, and big cap to create the simplest possible tube amp. Use it for guitars, use it for hi-fis, it’s all the same. It’s not going to sound great, but it is a very easy amp to build.

All of these interesting audio amplifier projects are curated on this new list! If you have a build that amplifies sound in an interesting way, don’t be shy, just drop [Adam] a message on Hackaday.io and he’ll add it. That’s it for this week’s Hacklet. As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Garbage Can CNC Machine Build

November 21, 2015 by Dan Maloney 41 Comments

Forget sourcing parts for your next project from some fancy neighborhood hardware store. If you really want to show your hacker chops, be like [HomoFaciens] and try a Dumpster dive for parts for a CNC machine build.

OK, we exaggerate a little – but only a little. Apart from the control electronics, almost everything in [HomoFacien]’s build could be found by the curb on bulk-waste pickup day. Particle board from a cast-off piece of flat-pack furniture, motors and gears from an old printer, and bits of steel strapping are all that’s needed for the frame of a serviceable CNC machine. This machine is even junkier than [HomoFacien]’s earlier build, which had a lot more store-bought parts. But the videos below show pretty impressive performance nonetheless.

Sure, this is a giant leap backwards for the state of the art in DIY CNC builds. but that’s the point – to show what can be accomplished with almost nothing, and that imagination and perseverance are more important for acceptable results than an expensive BOM.

With that in mind, we’re throwing down the gauntlet: can anyone build a CNC machine from cardboard and paperclips?

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Tiny Arcade, Based On Arduino

November 21, 2015 by Elliot Williams 16 Comments

Who can resist video games when they’re packed up in tiny, tiny little arcade machines? [Ken]’s hoping that you cannot, because he’s making a cute, miniature Arduino-based arcade game platform on Kickstarter. (Obligatory Kickstarter promo video below the break.)

The arcades are based on [Ken]’s TinyCircuits Arduino platform — a surprisingly broad range of Arduino modules that click together using small snap connectors in place of pin headers. The system is cool enough in its own right, and it appears to be entirely open source. Housing these bits in a cute arcade box and providing working game code to go along with it invites hacking.

There’s something about tiny video cabinets. We’ve seen people cram a Game Boy Advance into a tiny arcade cabinet and re-house commercial video game keyfobs into arcade boxes. Of course, there’s the Rasbperry Pi. From [Sprite_TM]’s cute little MAME cabinet to this exquisite build with commercially 3D-printed parts, it’s a tremendously appealing project.

But now, if you’re too lazy to build your own from scratch, and you’ve got $60 burning a hole in your pocket, you can get your own tiny arcade — and tiny Arduino kit — for mere money. A lot of people have already gone that route as they passed the $25k funding goal early yesterday. Congrats [Ken]!

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Robotic Tabletop

November 20, 2015 by Al Williams 19 Comments

Remember pin art? That’s the little box full of pins that you can push something into and the pins take on the shape. You usually use your hand, but any small object works (including, if you are brave enough, your face). [Sean Follmer] (formerly at the MIT Media Lab) developed the reverse of this: a surface made of pins driven by motors. Under computer control, the surface can take on shapes all by itself.

The square pins can be seen in the video below moving and manipulating blocks and using them to build structures out of the blocks. By using the right sequence of pin motions, the blocks can be flipped and even stacked. Magnetic blocks offer even more options.

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Turning A Car Into A Playstation Controller

November 20, 2015 by James Hobson 7 Comments

For a rather obscure brand advertisement, Nissan decided to turn one of their cars into a giant Playstation 4 controller to play a game of football (soccer).

The first question to pop into our heads was why? And that’s because Nissan is a major sponsor of UEFA Champions League. From there, it became why not? We love the companies that get their hands dirty on a hacking level, and actually do something instead of just funneling money into your standard billboard advertising — it’s just more fun this way.

The second question you should be asking yourself is how do you play soccer using a car? Well, it’s pretty simple. Steering is your left and right controls, the indicator switch is forward and backward, the windshield wipers kick the ball, a steering wheel button lets you run faster, the brake pedal passes the ball, and the gas pedal shoots. Simple right? As one of the prototype testers describes:

It’s kinda like tapping your head and rubbing your stomach at the same time, it really messes your head up — but it’s really enjoyable when you get it right.

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Stronger 3D Printed Parts

November 20, 2015 by Al Williams 25 Comments

When [hobbyman] wanted some 3D printed parts to attach a bag to his bike, he was worried that the parts would not be strong enough to hold when the bag was full. He decided to find a way to reinforce the part with fiberglass and epoxy. His first model had holes and grooves to be filled in with epoxy.

However, after working with the part for a bit, he decided to take a different approach. Instead of making the part nearly solid plastic with space for the epoxy, he instead created the part as a shell and then filled it with fibers and epoxy. After it all cured, a little sanding started removing some of the plastic shell and what was left was mostly a cast fiberglass part (although some of the plastic was left on).

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The Best Conference Badge Hacking You’ve Ever Seen

November 20, 2015 by Brian Benchoff 24 Comments

As with any proper hardware con, the Hackaday Supercon needed a badge, and preferably one that was electronic. This conference centered around hardware creation, and the badge was no exception.

Designed on a tight timeline, it was possible to deliver a PCB badge for the attendees but it didn’t include microcontrollers, FPGAs, or software defined radios. This blank slate was the foundation for a completely unconstrained freestyle electronics soldering session.

The front of the badge includes a matte black solder mask with Truchet tiles of traces. Put multiple badges edge-to-edge and the pattern continues indefinitely. Inside of each curved trace is a through-hole via and those makes up a grid of holes on the back of the badge. On that back side there are also two rectangular grids that presented a nice area to which hackers soldered their components.

More than a few people took up the challenge of hacking their badge, and despite a strange pitch for the through holes (0.230″), and traces that didn’t go anywhere, there were some amazing builds. I would go so far to say that the badge hacking at the Supercon was the best I’ve ever seen, and this includes DEFCON and CCC.