Google Contest Builds More Efficient Inverters

A few summers ago, Google and IEEE announced a one million dollar prize to build the most efficient and compact DC to AC inverter. It was called the Little Box Challenge, with the goal of a 2kW inverter with a power density greater than 50 Watts per cubic inch.

To put this goal into perspective, the DC inverter that would plug into a cigarette lighter in your car has a power density of about 1 or 2 Watts per cubic inch. Very expensive inverters meant for solar installations have a power density of about 5 Watts per cubic inch. This competition aimed to build an inverter with ten times the power density of what is available today.

Now, the results are in, and the results are extremely surprising. The best entry didn’t just meet the goal of 50 W/in³, it blew the goal out of the water.

The winning entry (PDF) comes from CE+T Power, and comes in a package with a volume of 13.77 in³. That’s a power density of 143 W/in³ for a unit you can hold in the palm of your hand. The biggest innovations come from the use of GaN transistors and an incredible thermal management solution.

Other finalists for this competition include Schneider Electric Team from France that managed a 100 W/in³ and a Virginia Tech team that managed a power density of 61.2 W/in³.

Thanks [wvdv2002] for the tip.

FAA Bans Drones For More Than Six Million People

In recent weeks, the FAA has solicited input from hobbyists and companies in the ‘drone’ industry, produced rules and regulations, and set up a registration system for all the quadcopters and flying toys being gifted over the holiday season. Whether or not the FAA is allowed to do this is a question being left to the courts, but for now, the FAA has assuredly killed a hobby for more than six million people. The FAA has introduced an updated Temporary Flight Restriction (TFR) for a 30-mile radius around Washington, DC.

The 30-mile TFR area

Previously, there had been a blanket ban on drones, UAS, and model aircraft within a 15-mile radius of a point inside Reagan National Airport. This point covered the District of Columbia proper, and the suburbs of Bethesda, College Park, and Alexandria – basically, everything inside the beltway, and a mile or two beyond. The new flight restriction for drones covers a vastly larger area – all of the DC metro area, Annapolis, half of Baltimore, and all of northern Virginia. This area encompasses a population of more than six million people.

The DC metro area has, since 9/11, become some of the most complex airspace in the entire country. There are several military bases, Aberdeen proving grounds, the US Naval academy, and of course the White House, Capitol building, and the Pentagon. Even commercial airliners are subject to some very interesting regulations. For the same reason general aviation shuts down in southern California every time the president visits LA, you simply can’t fly model aircraft within the beltway; it’s a security measure, and until now, flying clubs in the DC area have dealt with these restrictions.

The new TFR has effectively shuttered more than a dozen flying clubs associated with the Academy of Model Aeronautics. DCRC, a club with a field in the middle of some farmland in Maryland, has closed down until further notice. The Capital Area Soaring Association has also closed because of the TFR.

Although called a Temporary Flight Restriction, this is a rule that will be around for a while. The FAA says this restriction is here for good.

Scope Noob: Bridge Rectifier

Welcome back to this week’s installment of Scope Noob where I’m sharing my experiences learning to use my first oscilloscope. Last week I started out measuring mains frequency using an AC-AC wall wart adapter. Homework, for those following along, was to build a bridge rectifier and probe the signals from it. Let’s take a look.

Continue reading “Scope Noob: Bridge Rectifier”

Hackaday At MakeDC


Last Wednesday, our Hackaday travels took us to the Washington, DC area for a visit to NOVA Labs near Dulles and a yet-to-be opened Metro stop. Also on our itinerary was a visit to MakeDC, an informal get together for people around the nation’s capitol to show off their latest projects and builds.

The highlight of the evening was a pair of talks from [Julian] and [Taylor] on a project they did for work: a social cooler, or a locked box holding cool drinks that will only open when enough people send a text to a certain number. We’ve got [Julian]’s talk on video, but despite our fancy new camera gear for this sorta thing, [Taylor]’s demo of what an Electric Imp can do was lost to the digital wastes.

Aside from [Julian]’s talk on APIs and [Taylor]’s talk on the Electric Imp, there were a few impromptu presentations from the attendees. One of the most thorough was the duo from Shiny & Jackal Cosplay, crafters of EVA foam and LEDs. Truth be told, Hackaday doesn’t see many of these ‘softer’, cosplay and prop making builds in the tip line, and that’s a shame; the amount of skill that goes into these costumes is at least as equal as a woodsmith that can build fine furniture using only hand tools.

Perhaps a little premature, but TechShop is opening a new location in Arlington, VA at the end of the month. The GM [Addam Hall] was there scoping out the hacks and letting the attendees know there’s going to be a huge, awesome shop that’s down town in Crystal City. Close enough to public transportation, anyway, because anyone who drives in DC is certifiable.

The last item of note isn’t a build yet, but it’s shaping up to be pretty cool. It’s BRWRY – pronounced, ‘brewery’ – and will be a semi-automated beer making machine. Robots and beer, what can’t you love?

We’d like to thank [Zach], [Julian], [Taylor], and all the other guys from iStrategyLabs for putting together a nice evening of hanging out, drinking beer, eating pizza, and talking about what you’ve built. We had a great time, and we’re looking forward to the next one, as well as any other similar get together in other cities.

Searching For Makers In Washington DC


Despite there being an inordinate amount of techies and tech companies in the Washington, DC/Northern Virginia area, there aren’t really that many hacker/makerspaces, or really anywhere else for tinkering, building, and generally futzing around with a soldering iron. [Zach] thought it was time for a change and is now organizing the second Make DC an informal get together to show off your latest projects and builds. Here’s the best part: Hackaday is coming, and we’re bringing some sweet swag.

Right now [Matt] has two talks lined up focused on bringing APIs into the physical world. There’s space for plenty more speakers, so if you have something to show off be sure to sign up.

The event is scheduled for Wednesday, March 19, 6:30 PM, half a block away from the Dupont Circle Metro station. Be there. You’ll get a sticker at least.

Experimenting with bridge rectifers for AC to DC power conversion

The folks over at Toymaker Television have put together another episode. This time they’re looking at bridge rectifiers and how they’re used in AC to DC converters.

This is a simple concept which is worth taking the time to study for those unfamiliar with it. Since Alternating Current is made up of cycles of positive and negative signals it must be converted before use in Direct Current circuits; a process called rectification. This is done using a series of 1-way gates (diodes) in a layout called a bridge rectifier. That’s the diamond shape seen in the diagram above.

This episode, which is embedded after the break, takes a good long look at the concept. One of the things we like best about the presentation is that the hosts of the show talk about actual electron flow. This is always a quagmire with those new to electronics, as schematics portray flow from positive to negative, but electron theory suggests that actual electron flow is the exact opposite. Continue reading “Experimenting with bridge rectifers for AC to DC power conversion”

Power supplies and transformers; a learning experience

[Ladyada] is working on a tutorial series covering power supplies. If you’ve ever built an electronic project you’ve used some type of power supply but we think that most people have no idea how you get from mains power to the DC voltages that most small projects use. So if you want to learn, get started with the first installment which covers AC/DC converters based on a transformer like the one seen above.

These transformers are inside the heavy and hot wall-wart plugs that come with many electronics. We used one along with a breadboard power supply when building the pumpkin LED matrix. They use a pair of coils to step down the voltage to a much smaller level. From there it’s a matter of rectifying the AC into DC power, which she talks about in an easy to follow discussion.

We understand this type of converter quite well but we’re a bit foggy on switch-mode AC/DC converters that don’t use a transformer. They’re much better because you don’t have to build a regulator into the target project like you do with wall-warts. Can’t wait until she gets to that part of the series!