Learn to Translate IR Codes and Retransmit Using Arduino

EEVBlog IR transmitter

[Dave Jones] from EEVBlog.com takes “Arduino fan boys” off the garden path getting down and dirty with different methods to capture, evaluate and retransmit IR remote control codes. Capturing and reproducing IR remote control codes is nothing new, however, [Dave] carves his own roads and steers us around some “traps for young players” along the way.

[Dave] needed a countdown timer that could remotely start and stop recording on his Cannon video camera, which he did with simplicity in a previous EEVBlog post using a commercial learning remote control unit. The fans demanded better so he delivered with this excellent tutorial capturing IR codes on his oscilloscope from an IR decoder (yellow trace) as well as using an IR photo transistor (blue trace) which showed the code inclusive of 38 KHz carrier frequency. Either capture method could easily be used to examine the transmitted code. The second lesson learned from the captured waveforms was the type of code modulation being used. [Dave’s] remote transmitted NEC (Japanese) pulse length encoding — which can be assertaind by referencing the Infrared Remote Control Techniques (PDF). Knowing the encoding methodology it was trivial to manually translate the bits for later use in an Arduino transmitter sketch. We find it amazing how simple [Dave] makes the process seem, even choosing to write his own sketch to reproduce and transmit the IR codes and carrier instead of taking the easy road looking for existing libraries.

A real gem of knowledge in the video was when it didn’t work! We get to follow along as [Dave] stumbles before using a Saleae Logic analyzer to see that his transmitter was off frequency even though the math in his sketch seemed correct. Realizing the digital write routine was causing a slowdown he fudged his math to make the needed frequency correction. Sure, he could have removed the performance glitch by writing some custom port control but logic dictates using the fastest and simplest solution when hacking a one-off solution.

[Dave’s] video and links to source code after the break.

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The making of a katana hand guard

tiger

Even though the handmade portion of Hackaday is still in its infancy, we expected to put up a post on traditional japanese sword making by now. What [Kelvin] sent in to the tip line far surpases the artistry of forging a katana by hand. It’s a tsuba, the hand guard for a katana, and over the course of two videos (one and two), you can see this masterpiece of traditional metalworking techniques take shape.

Tsubas usually come in a matched set, one for the katana, or long sword, and another for the wakizashi, a slightly shorter sword. [Ford Hallam] was asked to construct the tsuba for a katana that had been lost to the sands of time. Fortunately, a black and white photograph of the original as well as the matching wakizashi tsuba were available for reference, making the design of this tsuba an exercise in replication.

The piece of metal this tsuba was constructed from is made out of a slightly modified traditional alloy of 75% copper and 25% silver. After the blank was cast, many, many hours of scraping, filing and hammering began before the design was laid out.

The craftsmanship in this tsuba is, quite simply, insane. There are about 100 different pieces of metal inlaid into the tsuba to emulate the tiger’s stripes, and hundreds of hours of work in hand carving every leaf and every bit of fur.

Even more, no power tools were used in the creation of this hand guard; everything was crafted using the same methods, tools, and materials as the original tsuba. A masterful piece of craftsmanship, indeed.

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Power suit for Japanese farmers

power_suit

Researchers at Tokyo University of Agriculture and Technology have been demoing a new power suit. It’s intended to be used by people hand harvesting in the farm industry. The 55 pound device supports the worker’s joints as they squat and reach. Within three years, they hope to have the cost within $10K. We’ve seen quite a few power suit devices this year, but research has been going on for many years, as you can see in our power suit roundup.

[Thanks Lane]

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