Color-Tunable LEDs Open Up Possibilities Of Configurable Semiconductors

May 6, 2019 by 26 Comments

The invention of the blue LED was groundbreaking enough to warrant a Nobel prize. For the last decade, researchers have been trying to take the technology to the next level by controlling the color of emission while the device is in operation. In a new research paper, by the guys over Osaka University, Lehigh University, the University of Amsterdam and West Chester University have presented a GaN LEDs that can be tuned to emit different colors from the same substrate.

GaN or Gallium nitride is a wide band-gap semiconductor that has been employed in the manufacturing of FETs that are known to have higher power density due to its high thermal capacity while increasing efficiency. In the the case of the tunable LED, the key has been the doping with Europium for creating energy bands. When an electron jumps from a higher band to a lower band, it emits energy in the form of light and the wavelength or color depends on the gap of energy jumped as per Plank-Einstein equation.

By controlling the current density and duty cycle, the energy jumps can be controller thereby controlling the color being emitted. This is important since it opens up the possibility of control of LEDs post production. External controllers could be used with the same substrates i.e. same LEDs to make a lamp of different intensity as well as color without needing different doping for R,G and B emissions. The reduction in cost as well as size could be phenomenal and could pave the way for similar semiconductor research.

We have covered the details of the LED in the past along with some fundamentals on the control techniques. We are hoping for some high speed color accurate displays in the future that don’t break the bank on our next gaming build.

Thanks for the tip [Qes]

A Hydrogen Fuel Cell Drone

May 6, 2019 by 37 Comments

When we think about hydrogen and flying machines, it’s quite common to imagine Zeppelins, weather balloons and similar uses of hydrogen in lighter-than-air craft to lift stuff of the ground. But with smaller and more efficient fuel cells, hydrogen is gaining its place in the drone field. Project RACHEL is a hydrogen powered drone project that involves multiple companies and has now surpassed the 60 minutes of flight milestone.

The initial target of the project was to achieve 60 minutes of continuous flight while carrying a 5 kg payload. The Lithium Polymer battery-powered UAVs flown by BATCAM allow around 12 minutes of useable flight. The recent test of the purpose-built fuel cell powered UAV saw it fly for an uninterrupted 70 minutes carrying a 5 kg payload.  This was achieved on a UAV with below 20 kg maximum take-off mass, using a 6-litre cylinder containing hydrogen gas compressed to 300 bar.

While this is not world record for drones and it’s not exactly clear if there will be a commercial product nor the price tag, it is still an impressive feat for a fuel cell powered flying device. You can watch the footage of one of their tests bellow:

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Web Interface Controls Nixie Tube Clock

May 5, 2019 by 12 Comments

We love our clocks around here and we love nixie tubes as well. The combination of the two almost seems to be a no-brainer. With the modern twist of an ESP8266, Reddit user [vladco] built a minimalist nixie tube clock.

The build starts with the nixie tubes, Russian In4s, each one mounted on its own small circuit board. Each board is chained together and they’re mounted on a wooden frame. The frame is mounted inside a nice wooden case which was designed in Fusion 360 and milled out of oak at a local hackerspace.

There are no controls on the case. No buttons or knobs. This clock is set via the EPS8266 which gets the time and updates the shift registers that set the numbers on each of the tubes. The clock dims at night so it’s not as bright. [vladco] wrote a web UI to set the time and interact with the  tubes.

The code and files for the case and circuit board are available online. The result is a nice, minimalist clock for your desk. There are plenty of clock builds on the site, several built from nixie tubes, including another nixie tube clock with an ESP8266, and another.

via Reddit

A Function Generator In Its Purest Form

May 5, 2019 by 9 Comments

If you have a modern function generator on your bench it is quite likely to contain a direct-digital synthesis circuit that creates arbitrary waveforms using a microprocessor controlled DAC. If you have a cheap function generator it’s likely to contain a one-chip solution that generates approximations to sine and triangle waveforms through modifying a square wave with a set of filters.

These methods both produce adequate waveforms for most of your function generator needs, but they are both far from perfect for the purist. Both methods introduce some distortion, and to address this [michal777] has produced a generator that takes the process back to basics with all stages implemented using building block ICs and transistors. The circuit follows the same square-wave-modifying path as the cheaper integrated devices, but with significant attention paid to the design to ensure that it does as good a job as possible. It also makes for a fascinating dive into function generator design.

The generator hardware has been neatly fitted onto a PCB with a riser for a set of front panel controls. He shares a few pictures of previous designs. We particularly like one that appears to have been fitted into a redundant cooking pot.

We’ve brought you a few function generators over the years. If you’ve got one of the cheaper examples, we’ve even covered how you might improve it a little.

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Hackaday Links: May 5, 2019

May 5, 2019 by 22 Comments

Simulacra and simulation and Kickstarter videos. The Amigo Robot is a 4-wheeled omnibot robot on Kickstarter. It does STEM or STEAM or whatever. Oh neat, injection molded magnetic pogo pins, that’s cool. Watch the video for this Kickstarter, it is a work of postmodern horror. We live in a post-reality world, and this is beyond parody.  You have the ubiquitous cheerful whistling, a ukulele, tambourine and a glockenspiel. You’ve got a narrator that falls squarely into the uncanny valley and a cadence that could have only been generated by a computer. You’ve got grammar that is very much correct, but somehow wrong; ‘It is the key to interact with family pets’. This is really, really bad.

Who is Satoshi? The creator of Bitcoin, a person or persons known as Satoshi Nakamoto, has been an open question for years now, with many people claiming they are the one that invented Bitcoin (with the implication that they’re in control of the first coins and therefore a multi-Billionaire). Newsweek found someone named Dorian Nakamoto, but that guy didn’t make Bitcoin. Wired magazine used back-dated blog posts to identify the creator of Bitcoin. Needless to say, the creator of Bitcoin has not been identified yet. Now, there’s an unveiling of sorts coming up. gotsatoshi.com has a live countdown and doesn’t use Rockapella as a house band. This bears repeating, again: there is exactly one way to prove the identity of Satoshi Nakamoto. To prove you are Satoshi, all you need to do is move some of the first Bitcoins. That’s it, that’s all you need to do, and it’s not going to happen when the gotsatoshi.com countdown hits zero.

CNC machines controlled by a Pi abound, but here’s a word of warning about buying a ‘bargain’ CNC machine from China from [Rob] via our tips line:

In the “homebrew” community, I know some people have their own CNC machines – I’ve seen a hundred and one projects using Raspberry Pis to run homemade CNCs and so on, so I guess there is a good supply of open-source/freeware to software to control them with.
However, some people, like a mate at work, might be tempted by a good “bargain” from China.  No names, no pack drill, but just before last Christmas, my mate bought a “cheap” CNC system from China – It was about three or four thousand Euros, if I remember rightly.  It has been working well and he done some work for our work as well. No problems.
Last week, our firm was contacted by Siemens. They claimed that someone at our firm has been using unlicensed Siemens software.  At first no-one knew what they were on about.  Someone thought it might be about some CAD system or other – we had been trialing a few to see which suited us best, but we had stuck well within the restrictions for the trials.
Then we found out it was the software on his CNC machine.  Because he had used his work laptop with it, the system had “phoned home” and alerted Siemens that an unlicensed version was being used.  Siemens then demanded EUR 32,000 – yes, thirty two THOUSAND Euros to license the software.  That was something like EUR 27,000 for the commercial license and EUR 5 000 for the second one.  It was explained that he had bought the CNC system from where-ever and had a license issued by the manufacturer.  I license that Siemens do not acknowledge.  They have now accepted that he bought and used it in good faith that it was fully legit, so they waived the commercial license and are now demanding “only” EUR 5,000, but that still comes with the threat – pay up or we take you to court…

We’re all very familiar that Dassault Systems will start hitting you up for that Solidworks license you didn’t pay for, but this is effectively firmware for a CNC machine that is phoning home through a laptop. In effect it’s a reverse Stuxnet, brought to you by a cheap Chinese CNC machine.

Here’s a hot tip for anyone who wants to do something people want. Direct to garment printers (DTG printers) are pretty much inkjet printers modified to print on t-shirts. ‘dtg printer’ is one of Hackaday’s perennial top search terms, most likely because of a post we did ten years ago. If you want to join the cool kids club and do something people desperately want, find a cheap inkjet and turn it into a DTG printer.

Red Hat has changed its logo. Red Hat, the company that somehow makes money on Open Source software, changed their logo this week. The branding for Red Hat hasn’t been very good since 2016 or thereabouts, and the branding for the Fedora project has been taking hits for just as long, m’lady. Beyond that, customer surveys revealed that the old ‘Shadowman’ logo evoked feelings like, ‘sinister, secretive, evil, and sneaky’. The new logo removes the shadowman entirely, and makes the hat the focus of attention. There is now official confirmation that there is a black band around the crown of the hat (in the Shadowman logo, this band could be confused for a shadow), and the crown is sharper. The jury is still out on the fedora vs. trilby argument, and indeed the argument is even more divisive now: the difference between a trilby and a fedora is in how they are worn, and by removing the Shadowman from the logo we now have fewer context clues to make the determination. Bet you didn’t think you were going to read two hundred words about the Red Hat logo today, did you?

Ripping Up A Rothult

May 5, 2019 by 27 Comments

NFC locks are reaching a tipping point where the technology is so inexpensive that it makes sense to use it in projects where it would have been impractical months ago. Not that practicality has any place among these pages. IKEA carries a cabinet lock for $20USD and does not need any programming but who has a jewelry box or desk drawer that could not benefit from a little extra security? Only a bit though, we’re not talking about a deadbolt here as this teardown shows.

Rothult has all the stuff you would expect to find in an NFC scanner with a moving part. We find a microcontroller, RFID decoder, supporting passives, metal shaft, and a geartrain. The most exciting part is the controller which is an STM32L051K8 processor by STMicroelectronics and second to that is the AS3911 RFID reader from AMS. Datasheets for both have links in the teardown. Riping up a Rothult in the lab, we find an 25R3911B running the RFID, and we have a link to that PDF datasheet. Both controllers speak SPI.

There are a couple of things to notice about this lock. The antenna is a flat PCB-mounted with standard header pins, so there is nothing stopping us from connecting coax and making a remote antenna. The limit switches are distinct so a few dabs of solder could turn this into an NFC controlled motor driver. Some of us will rest easy when our coworkers stop kidnapping our nice pens.

Rothult first came to our attention in a Hackaday Links where a commenter was kind enough to tip us off to this teardown. Thanks, Pio! If this whets your appetite for NFC, we have more in store.

3D Printed Weather Station Gets A Wireless Upgrade

May 5, 2019 by 15 Comments

A weather station can be anything from a fun home science exercise, all the way up to a useful tool for planning and weather prediction. [Rob Ward] is one such person who has developed their own weather station, and it recently got a wireless upgrade.

We first featured [Rob]’s work back in 2018, noting that a largely 3D-printed weather station was a particularly useful tool for the home experimenter. The utility of this is now improved, with the addition of a 433 MHz wireless link from the weather sensors back to the base station. Over on Github, [Rob] does a great job of explaining the basics of the Manchester encoding scheme used, and has developed a system that can decode signals from Oregon Scientific weather stations, too.

[Rob] uses the weather station to report weather conditions at Lake Tyers Beach, providing useful information for anyone in the area who might be considering a visit to the coast. It’s not quite as fun as asking whoever’s around on the CB road channel, but it’s a darn sight more accurate for your trouble. Video after the break.

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