Easy Parabolic Mirror from a Trash Can Lid

Parabolic reflectors for solar applications are nice stuff, and making your own is a great project in itself. One of the easiest ways we have seen is that of [GREENPOWERSCIENCE], who uses nothing more than a trash can lid, mylar film, and tape. You need a way to make a partial vacuum though.

The idea is so simple that it´s almost like cheating. Cut a circle of mylar slightly larger than the lid, and tape it all around, taking care of stretching the mylar in the process. After you´re done with this, you end up with a nice flat mirror. Here´s where the vacuum is needed to force the film into parabolic shape. Extract the air from a little hole in the lid that was previously drilled, and tape it to prevent the loss of the vacuum. The atmospheric pressure on the mylar film will take care of the job, and magically you get a nearly-parabolic reflector ready for work.

In this other video, you can see the reflector in action burning stuff. One obvious problem with this technique is the loss of the vacuum after some time, about an hour according to the author. Here´s another way to make a more durable mirror also with mylar as the reflecting element, however the quality of the resulting mirror is not as good.

 

Surf’s Up! Virtually

While it may or may not be true that if everybody had an ocean they’d be surfing like California, it is true that with a water pump, some copper tape, and a few scraps you can make a surfing simulator that sprays you if you don’t keep your balance.

You can see the simple device in operation in the video below. We presume [Adi_10] actually surfs, but we can’t comment on the realism of the simulator. There’s no computer. Just a switch made from the base and the balance board.

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Wii U RetroPie Console Looks Gorgeous

What to do with your broken gaming consoles? Gut it and turn it into a different gaming console! Sudomod forum user [banjokazooie] has concocted his own RetroPie console from the husk of a WiiU controller — an ingenious demonstration of how one can recycle hardware to a perfectly suited purpose.

[banjokazooie] actually used an original shell for this build, but if you happen to have a broken controller around — or know someone who does — this is a great use for it. A Raspberry Pi 3 is the brains of this operation (not counting [banjokazooie]), and it features a 6.5″ HDMI display, a Teensy 2.0 setup for the inputs, a headphone jack with automatic speaker disconnection, dual 3400 mAh batteries, an external SD card slot, and a lot of hard work on the power supply circuit — although [banjokazooie] reports that the hardest part was cutting to size a custom PCB to mount it all on. The original plan was to see if the idea was possible, and after a three month effort, it appears to work beautifully.

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After The Prize: Chipwhisperer

We’re less than a week away from the Hackaday Superconference, where we’ll be announcing the winners of the Hackaday Prize. The Hackaday Prize is a celebration of the greatest hardware the Hackaday community has to offer, and in the past three years we’ve been running this amazing contest, we’ve seen some awesome stuff.

While not every project entered into the Hackaday Prize has gotten off the ground — the lawnmower-powered killacopter of decapitation is still tethered to its test stand — there have been some spectacular projects over the past few years that have already had an incredible impact in industry, academia, and the security industry. For the next few days, we’re going to revisit these projects, see how they’re doing, and look at the impact they’ve had on the world of Open Source hardware.

The first project we’re taking a look at is the ChipWhisperer a tool created by Colin O’Flynn to look at the secret insides of chips and firmware despite whatever embedded security is enabled on said chip. The ChipWhisperer was an entry into the first Hackaday Prize where it won second place. Since then, the ChipWhisperer has become the de facto hardware tool for investigating clock glitching, side channel analysis, and other exotic magic tricks that make security analysis so much fun.

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New Lithium Battery Technology Takes Guts

Researchers have built a prototype lithium-sulphur battery that — when perfected — could have up to five times the energy density of current lithium-ion devices. Researchers in the UK and China drew inspiration from intestines to overcome problems in the battery construction.

In your intestine, small hair-like structures called villi increase the surface area that your body uses to absorb nutrients from food. In the new lithium-sulphur battery, researchers used tiny zinc oxide wires to form a layer of material with a villi-like structure. These villi cover one electrode and can trap fragments of the active material when they break off, allowing them to continue participating in the electrochemical reaction that produces electricity.

Lithium-sulphur batteries aren’t new (in fact, they were used in 2008 in a solar-powered plane that broke several records), but this new technique may make them more practical. You can see a video about ordinary lithium-sulphur batteries below along with more on how this research improves the state of the art.

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SSH Enters the Mosh Pit

With so many systems depending on Linux, the secure shell SSH has become a staple for many developers. If you are connected to your Raspberry Pi via a cable or a wireless router a few feet away, SSH can provide you with an encrypted connection straight to the box. However, if you have a system out in a swamp somewhere with intermittent slow network access, SSH can be a real pain. When your IP address can change (for example, roaming on a cellular network), SSH has problems, too.

To combat these and other problems, you might consider an open source program called Mosh (mobile shell). There’s two parts to Mosh. One part works as a server while the other is the client application. Neither of these require root access. You can see a video about Mosh below.

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Pi Cart: 2,400 Games In One

What’s the quickest way to turn one game into 2,400? Cram a Raspberry Pi Zero running RetroPie into an NES cartridge and call it Pi Cart.

This elegant little build requires no soldering — provided you have good cable management skills and the right parts. To this end, [Zach] remarks that finding a USB adapter — the other main component — small enough to fit inside the cartridge required tedious trial and error, so he’s helpfully linked one he assures will work. One could skip this step, but the potential for couch co-op is probably worth the effort.

Another sticking point might be Nintendo’s use of security screws; if you have the appropriate bit or screwdriver, awesome, otherwise you might have to improvise. Cutting back some of the plastic to widen the cartridge opening creates enough room to hot glue in the USB hub, a micro USB port for power, and an HDMI port in the resulting gap. If you opted to shorten the cables, fitting it all inside should be simple, but you may have to play a bit of Tetris with the layout to ensure everything fits.

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