How Low-Power Can You Go?

September 1, 2017 by 28 Comments

[lasersaber] has a passion: low-power motors. In a bid to challenge himself and inspired by betavoltaic cells, he has 3D printed and built a small nuclear powered motor!

This photovoltaic battery uses fragile glass vials of tritium extracted from keychains and a small section of a solar panel to absorb the light, generating power. After experimenting with numerous designs, [lasersaber] went with a 3D printed pyramid that houses six coils and three magnets, encapsulated in a glass cloche and accompanied by a suitably ominous green glow.

Can you guess how much power and current are coursing through this thing? Guess again. Lower. Lower.

Under 200mV and 20nA!

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Ethereum: GPU Mining Is Back But For How Long?

September 1, 2017 by 66 Comments

By now, everyone and their dog has at least heard of Bitcoin. While no government will accept tax payments in Bitcoin just yet, it’s ridiculously close to being real money. We’ve even paid for pizza delivery in Bitcoin. But it’s not the only cryptocurrency in town.

Ethereum initially launched in 2015 is an open source, it has been making headway among the 900 or so Bitcoin clones and is the number two cryptocurrency in the world, with only Bitcoin beating it in value. This year alone, the Ether has risen in value by around 4000%, and at time of writing is worth $375 per coin. And while the Bitcoin world is dominated by professional, purpose-built mining rigs, there is still room in the Ethereum ecosystem for the little guy or gal.

Ethereum is for Hackers

There may be many factors behind Ethereum’s popularity, however one reason is that the algorithm is designed to be resistant to ASIC mining. Unlike Bitcoin, anyone with a half decent graphics card or decent gaming rig can mine Ether, giving them the chance to make some digital currency. This is largely because mining Ethereum coins requires lots of high-speed memory, which ASICs lack. The algorithm also has built-in ASIC detection and will refuse to mine properly on them.

Small-scale Bitcoin miners were stung when the mining technology jumped from GPU to ASICs. ASIC-based miners simply outperformed the home gamer, and individuals suddenly discovered that their rigs were not worth much since there was a stampede of people trying to sell off their high-end GPU’s all at once. Some would go on to buy or build an ASIC but the vast majority just stopped mining. They were out of the game they couldn’t compete with ASICs and be profitable since mining in its self uses huge amounts of electricity.

Economies of scale like those in Bitcoin mining tend to favor a small number of very large players, which is in tension with the distributed nature of cryptocurrencies which relies on consensus to validate transactions. It’s much easier to imagine that a small number of large players would collude to manipulate the currency, for instance. Ethereum on the other hand hopes to keep their miners GPU-based to avoid huge mining farms and give the average Joe a chance at scoring big and discovering a coin on their own computer.

Ethereum Matters

Ethereum’s rise to popularity has basically undone Bitcoin’s move to ASICs, at least in the gamer and graphics card markets. Suddenly, used high-end graphics cards are worth something again. And there are effects in new equipment market. For instance, AMD cards seem to outperform other cards at the moment and they are taking advantage of this with their release of Mining specific GPU drivers for their new Vega architecture. Indeed, even though AMD bundled its hottest RX Vega 64 GPU with two games, a motherboard, and a CPU in an attempt to make the package more appealing to gamers than miners, AMD’s Radeon RX Vega 56 sold out in five minutes with Ethereum miners being blamed.

Besides creating ripples in the market for high-end gaming computers, cryptocurrencies are probably going to be relevant in the broader economy, and Ethereum is number two for now. In a world where even banks are starting to take out patents on blockchain technology in an attempt to get in on the action, cryptocurrencies aren’t as much of a fringe pursuit as they were a few years ago. Ethereum’s ASIC resistance is perhaps its killer feature, preventing centralization of control and keeping the little hacker in the mining game. Only time will tell if it’s going to be a Bitcoin contender, but it’s certainly worth keeping your eye on.

An Environmentally Conscious, Solar-Powered Throwie

September 1, 2017 by 24 Comments

The basic throwie is a a type of street art/graffiti/vandalism — depending on where you stand — consisting of a coin cell, an led, and a magnet taped together. Seeking to be a slightly more eco-friendly troublemaker, [Alaric Loftus] has kindly put together an Instructable on how to build a solar-powered throwie!

In order to be the best maker of mischief possible, [Alaric Loftus] tried a number of different products to find one that was hackable,  supplied the right voltage, had the right form factor, and cheap enough to literally throw away. Turns out, garden path lights hit that sweet spot. Once [Alaric Loftus] has drilled a hole in the light and opened it up, de-soldering the stock LED, attaching some leads to the contacts and sticking it into the freshly-drilled hole is simply done. Hot-gluing a strong magnet on the bottom completes the throwie.

[Alaric Loftus] also advises that drilling the LED hole slightly smaller and sealing up any cracks with hot glue will strengthen its water resistance — because if it’s worth doing, it’s worth doing it right.

We’ve featured some really cool — even creepy — takes on the throwie concept, but please don’t contribute any further to e-waste buildup.

A Compact, Portable Pantograph Camera Slider

September 1, 2017 by 14 Comments

Ho, hum, another camera slider, right? Wrong — here’s a camera slider with a literal twist.

What sets [Schijvenaars]’ slider apart from the pack is that it’s not a slider, at least not in the usual sense. A slider is a mechanical contrivance that allows a camera to pan smoothly during a shot. Given that the object is to get a camera from point A to point B as smoothly as possible, and that sliders are often used for long exposures or time-lapse shots, the natural foundation for them is a ball-bearing linear slide, often powered by a stepper motor on a lead screw. [Schijvenaars] wanted his slider to be more compact and therefore more portable, so he designed and 3D-printed a 3-axis pantograph mechanism. The video below shows the slider panning the camera through a silky smooth 60 centimeters; a bonus of the arrangement is that it can transition from panning in one direction to the other without any jerking. Try that with a linear slider.

Granted, this slider is not powered, but given that the axes are synced with timing belts, it wouldn’t be difficult to add a motor. We’ve seen a lot of sliders before, from simple wooden units to complicated overhead cranes, but this one seems like a great design with a lot of possibilities.

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Wearable Foxhunt Transmitter For Conventions

August 31, 2017 by 13 Comments

Amateur radio operator [KE4FOX] wanted to build his own 2M fox hunt transmitter for use at conventions. It would be contained in a 1020 Pelican micro case and attached to a person who would walk around transmitting a signal, leaving the hams to track down the fox. The project uses a DRA818 VHF/UHF transceiver plugged into a low-pass filter combined with a hardware DTMF decoder, all controlled by an ATmega328P and powered by a 11.2 mAh battery.

[KE4FOX] also etched his own PCB, using the PCB toner transfer method, folding a sheet of transfer paper around the board to align both layers. Then he etched the board using cupric chloride. When assembling the board he realized he had made a terrible error, assuming the transceiver module’s pins went in the top layer when in fact they should have gone in the bottom layer. He solved this by soldering in the module in upside down.

He dropped the project into the 1020 and installed an SMA antenna. After he assembled the project he found out that the level shifter he used on the Arduino’s 5 V data didn’t work as expected and it was stuck at a single frequency. Something to work on for V2!

We publish a large number of amateur radio posts here on Hackaday, including fox hunting with Raspberry Pi and how to make a TDOA directional antenna.

[thanks, that Kat!]

Open Source Barbot Needs Only Two Motors

August 31, 2017 by 16 Comments

Most drinkbots are complicated—some intentionally so, others seemingly by design necessity. If you have a bunch of bottles of booze you still need a way to get it out of the bottles in a controlled fashion, usually through motorized pouring or pumping. Sometimes all thoe tubes and motors and wires looks really cool and sci fi. Still, there’s nothing wrong with a really clean design.

[Lukas Šidlauskas’s] Open Source Barbot project uses only two motors to actuate nine bottles using only a NEMA-17 stepper to move the tray down along the length of the console and a high-torque servo to trigger the Beaumont Metrix SL spirit measures. These barman’s bottle toppers dispense 50 ml when the button is pressed, making them (along with gravity) the perfect way to elegantly manage so many bottles. Drink selection takes place on an app, connected via Bluetooth to the Arduino Mega running the show.

The Barbot is an Open Source project with project files available from [Lukas]’s GitHub repository
and discussions taking place in a Slack group.

If it’s barbots you’re after, check out this Synergizer 4-drink barbot and the web-connected barbot we published a while back.

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Fail Of The Week: Arduino Sand Matrix Printer

August 31, 2017 by 29 Comments

NYC beaches are where tropical beaches addicted to meth go to die. So says [Vije Miller] in his write-up for his Arduino sand matrix printer. It’s a clever idea, five servo-operated cardboard plungers that indent a pattern of dots in the sand as the device is pulled forward, resulting in something not unlike a dot matrix printer that can write messages in the sand.

He’s submitted it to us as a Fail Of The Week, because it doesn’t do a very good job of writing in the sand, and it’s burned out a servo. But we feel this isn’t entirely fair, because whether or not it has delivered the goods it’s still an excellent build. Cardboard isn’t a material we see much of here at Hackaday, but in this case he’s mastered it in a complex mechanism that while it may have proved a little too flexible for the job in hand is nevertheless a rather impressive piece of work.

You can see a brief video below the break showing it in action. He tells us his motivation has waned on this project, and expresses the hope that others will take up the baton and produce a more viable machine.

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