Jan 29, 2015

World's Smallest Chess Program

posted by Jim Turley

Chess is tough, right? It's a complicated game. Just explaining the rules can take hours, or hundreds of pages, and that's before you get into subtle strategies. Mastering chess can be the work of a lifetime.

So how did a French kid write a fully featured chess program in just 487 bytes of code? Not 487 MB. Not even 487 KB. It's four hundred and eighty-seven bytes of code. And it plays chess. This kid is good.

In case you're wondering, the previous record holder for smallest chess program was Sinclair ZX1 Chess, which weighed in at 672 bytes, a tiny chess record it held for 33 years. There's also Tiny Chess, a 1251-byte program. It offers graphics (as opposed to ASCII art), but since it's written in Javascript, it's not technically a standalone program, requiring megabytes of overhead to run.

 

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Jan 28, 2015

Rezence Wireless Charging Takes Steps

posted by Bryon Moyer

There have been a couple of developments in the wireless power world over the last couple months, both involving the new Rezence standard. You may recall that this is the new high-frequency resonant approach, as contrasted with the established lower-frequency Qi approach. We’ve reviewed the differences and proliferating standards before.

While Rezence beat out Qi in terms of establishing a resonant (as opposed to inductive, which is what legacy Qi is) standard, Qi (a resonant version of which is in the works) benefits from established infrastructure and channels. And standards aren’t product. So the Rezence allies have been trying to spin up infrastructure and design enablement so that they can get products on the market. Only then can they say that their approach has been truly proven and validated.

Late last year, they took another step in that direction. WiTricity released a development kit, the WiT-5000C3, to make it easier for designers to leverage the Rezence standard. The kit contains:

  • A full-on reference design for a Class 3 charger (up to 2 smartphones or 1 tablet);
  • Sample PTUs (power transfer units, aka chargers) and PRUs (power receive units, or chargees);
  • Engineering eval tools; and
  • A full set of documents.

WiT-5000C3_system.png

 (Image courtesy WiTricity)

One thing I noticed in the release was a reference to “classes” and “categories.” As in, this design is for a Class 3 charger, compatible with Category 3 devices and with tablets.

I inquired further into what this meant, and WiTricity sent the following tables. You can tell the standards folks had a task of choosing similar but different words for PTUs and PRUs. PTUs come in “classes”; PRUs come in “categories.” There’s no rule linking a particular class number to a category number – not in terms of what mates with what, nor in terms of power level.

Tables.png

As a Class 3 charger, then, it should be able to charge, at a minimum, one Category 4 device (tablet or phablet) and must support the maximum number of devices, two Category 3 units (smartphones). Just so happens that, from a power standpoint, 2x(Category 3) = Category 4…

Meanwhile, the expected merger between the Alliance for Wireless Power (A4WP) and the Power Matters Alliance (PMA) organizations was announced: a letter of intent has been signed, and the deal should complete mid-year.

While this was touted as proving that a “standards war” isn’t necessary, it also represents a blending of two relatively similar approaches. There’s a much bigger gap between the remaining two organizations. And, as far as I can tell, there’s little chance of further diplomacy. Both remaining sides – high- and low-frequency charging – remain firmly committed to their approaches.

You can find out more in the WiTricity dev kit announcementand the merger announcement.

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Jan 27, 2015

More than Memory

posted by Bryon Moyer

I don’t know about you, but when I hear “Spansion,” I hear memory. But there’s more going on there these days than FLASH. I talked with them last November when they were exhibiting at the IDTechEx show, which is partly about energy harvesting.

In particular, they acquired Fujitsu Microelectronics a year or so prior to broaden their product line. What they got were microcontrollers, with lots of digital and analog connectivity, and analog – primarily power management ICs (PMICs).

With this, they’re gunning for the internet of things (IoT). Surprise! Bet you didn’t see that coming… But they think that batteries are slowing adoption of IoT technology due to their need for low voltages and currents.

So their contribution to this situation is a couple of PMICs for energy harvesting – one is buck (drops in the incoming voltage); the other is boost (although it can drop voltage too if both needed).

Combined.png

 (Image courtesy Spansion)

The MB39C811 is targeted at regulating the voltages generated by solar (dye-sensitized cell and amorphous silicon) and vibrations (through piezoelectric or electret harvesters). The MB39C831 targets all solar as well as thermal harvesting.

They’re targeting industrial applications with these, so they’re pretty full-featured. They’re also working on slimmed-down versions for wearables.

They also have a simulator they call EasyDesign for configuring the energy harvesting module. Based on the needs of the node being powered, it can help determine, for example, how big a solar array is needed, and what the follow-on circuits should look like.

You can find more on their energy-harvesting PMIC page

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