The Easiest Infinity Mirror Build

Infinity mirrors are awesome. They’re great conversation pieces, and even more fun to stare into forever and ever and ever and ever… They can be tricky to build, but there’s actually a really easy way to do it, and [William] shows us how.

The way a infinity mirror works is it uses a one-way mirror with lights around the perimeter in front of a regular mirror. The majority of the light gets bounced back and forth between the two mirrored surfaces, and because you can see into the one-way mirror, you get that really cool infinity effect.

Now if you went out and bought a one way mirror, built the frame, and put it all together — it’d be a lot of work. But there’s an easier way to do it on the cheap. Mirrored car tint foil. Although it’s illegal on your car in most states, it’s still pretty easy to find.  Continue reading “The Easiest Infinity Mirror Build”

Physical Fitness for the Truly Lazy

We’re going to get in shape around here, starting today. Well… in the United States, it is almost Thanksgiving, so we might as well wait until… but then it is going to be the end of the year and between Christmas, Hanukkah,  and New Year’s, we should put it off until then.

OK, we get it. There’s always some excuse. We know we should go on and do some push ups today. Of course, we are a lazy bunch, so not everyone’s going to do a full push up. Then we’ll all argue how many we actually did. If this sounds like you, maybe you need an Arduino-based project that counts proper push ups.

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FleaFPGA + Arduino Uno = FleaFPGAUno

Some things are better together: me and my wife, peanut butter and jelly, and FPGAs and Arduino Unos. Veteran hacker [Valentin Angelovski] seems to agree: the FleaFPGA Uno is his latest creation that combines an FPGA (a Lattice MachX02 700HC) with an Arduino-compatible CPU.

It’s a step-up model from the origional FleaFPGA. With a few other components thrown in (such as a HDMI and composite video output and a WiFi option), you have a killer combination for experimenting with FPGAs or building an embedded system. That is because the Arduino part frees the FleaFPGA Uno from the breadboard: you can easily program, control and interface with the FPGA over a serial line or a wireless link using the Arduino IDE. There is even support for Arduino shields (albeit only 3.3V ones), making it even more expandable. This would be an awesome starting point for a retro gaming system, as many 8-bit consoles can be easily emulated in an FPGA. [Valentin] is currently selling the boards directly, and they are very reasonably priced at $50 or $60 for the WiFi version.

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DOE Announces a High Performance Computing Fortran Compiler Agreement

The U.S. Department of Energy’s National Nuclear Security Administration (NNSA) and its three national labs this week announced they have reached an agreement for an open-source Fortran front-end for Higher Performance Computing (HPC). The agreement is with IBM? Microsoft? Google? Nope, the agreement is with NVIDIA, a company known for making graphics cards for gamers.

The heart of a graphics card is the graphics processor unit (GPU) which is an extremely powerful computing engine. It’s actually got more raw horsepower than the computer CPU, although not as much as many claim. A number of years ago NVIDIA branched into providing compiler toolsets for their GPUs. The obvious goal is to drive sales. NVIDIA will use as a starting point their existing Fortran compiler and integrate it with the existing LLVM compiler infrastructure. That Fortran, it just keeps chugging along.

You can try out GPU programming on your Raspberry Pi. Yup! Even it has one, a Broadcom. Just follow the directions from Raspberry Pi Playground. You’re going to get your hands dirty with assembly language so this is not for the faint hearted. One of the big challenges with GPUs is exchanging data with them which gets into DMA processing. You could also take a look at [Pete Warden’s] work on using the Pi’s GPU.

Still wondering about the performance of CPU vs GPU? Here’s Adam Savage taking a look…

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Building A Better 3D Printed Gun

Back in 2013, [Cody Wilson] of Defense Distributed designed and built the world’s first completely 3D printed pistol. He called his gun the Liberator, after a World War II-era single-shot pistol designed to be cheap and easy to manufacture, easy to conceal, and for members of the French Resistance, ‘a great gun to obtain a better gun’.

cyl[Cody]’s Liberator turned out to be a great gun to obtain two or three fewer fingers. Not only was this a single-shot pistol, it was a single barrel pistol; with each round fired requiring a new 3D printed barrel. Tests were carried out, explosions happened, and we couldn’t even get the thing to print. For all the media hubbub, for all the concerned legislators, the first 3D printed pistol was much ado about nothing.

3D printers are still an extremely interesting technology, and if history has proved one thing, it’s that engineers and tinkerers will keep building guns. Last week, [James Patrick] released his latest design for a working 3D printed gun. It still fires the .22lr of the Liberator, but this is a double action revolver, it won’t blow up, and if you drop it, it won’t discharge. It’s the little things that count.

[James]’ revolver is either a 6 or 8-shot revolver uses a pepper-box design, where the gun has multiple chambers and barrels in one gigantic cylinder. The double action design first rotates the cylinder to the next chamber, pulls back a striker loaded up with a firing pin nail, and (hopefully) fires a round. In the video below, [James] goes over the design of his action, and ends up showing off a few test firings of his newly designed gun.

What’s very interesting about this build is how closely the development of 3D printed firearms is following the development of historical firearms. First, we had guns that probably shouldn’t be fired, ever. Now, the technology for 3D printed guns is about up to 1830 or thereabouts. Give it a few more years and we’ll be up to 1911.

Disclaimer: if you live in the US and think this sort of thing should be illegal, contact your state representative and tell them you support a constitutional convention to remove the personal right to own and operate firearms. This right has been upheld many, many times by the judiciary, and a constitutional convention is the only way your wishes could be carried out. Your state representative probably doesn’t read Hackaday; there is no need to comment here. Let’s talk about engineering and technology instead.

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Hacklet 85: Alternative Audio Amplifiers

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 that are more than just power amps, and exceedingly useful, to boot.

1601181393316190625[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.

973501443636885535What 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.


2981611414932529525Continuing 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 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!

Garbage can CNC Machine Build

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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