Alexa, Sudo Read My Resistor! A Challenge for Hackers

Nothing makes us feel more like we’re on Star Trek then saying “Computer, turn on desk light,” and watching the light turn on. Of course, normal people would have left the wake up word as “Alexa,” but we like “Computer” even if it does make it hard to watch Star Trek episodes without the home automation going crazy.

There’s a lot of hype right now about how voice recognition and artificial intelligence (AI) are transforming everything. We’ve even seen a few high-profile types warning that AI is going to come alive and put us in the matrix or something. That gets a lot of press, but we’re not sure we are even close to that, yet. Alexa and Google’s similar offerings are cool, there’s no doubt about it. The speech recognition is pretty good, although far from perfect. But the AI is really far off still.

Today’s devices utilize two rather rudimentary parts to provide an interaction with users. The first is how the devices pattern match language; it isn’t all that sophisticated. The other is the trivial nature of many of the apps, or — as Alexa calls them — skills. There are some good ones to be sure, but for every one useful application of the technology, there’s a dozen that are just text-to-speech of an RSS feed. Looking through the skills available we were amused at how many different offerings convert resistor color codes back and forth to values.

There was a time when building electronics meant learning the resistor color code. With today’s emphasis on surface mount components, though, it is less useful than it used to be. Still, like flossing, you really ought to do it. However, if you have an Amazon Alexa, it can learn the color code for you thanks to [Dennis Mantz].

Don’t have an Alexa? You can still try it in your browser, as we will show you shortly. There are at least eight similar skills out there like this one from [Steve Jernigan] or [Andrew Bergstrom’s] Resistor Reader.

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Handheld Network Analyzer Peek Inside

[Shahriar] recently posted a review of a 6.8 GHz network analyzer. You can see the full video — over fifty minutes worth — below the break. The device can act as a network analyzer, a spectrum analyzer, a field strength meter, and a signal generator. It can tune in 1 Hz steps down to 9 kHz. Before you rush out to buy one, however, be warned. The cost is just under $2,000.

That sounds like a lot, but test gear in this frequency range isn’t cheap. If you really need it, you’d probably have to pay at least as much for something equivalent.

[Shahriar] had a few issues to report, but overall he seemed to like the device. For example, setting the step size too broad can cause the spectrum analyzer to miss narrow signals.

If your needs are more modest, we’ve covered a much simpler (and less expensive) unit that goes to 6 GHz. If you need even less, an Arduino can do the job with a good bit of help. The Analog Discovery 2 also has a network analyzer feature, along with other tools at a more affordable cost, too. Of course, that’s only good to 10 MHz.

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Everything’s a Touch Surface with Electrick

Touch screens are great, but big touchscreens are expensive and irregular touchscreens are not easy to make at all. Electrik is a method developed by several researchers at Carnegie Mellon University that makes almost any solid object into a touch surface using tomography. The catch is that a conductive coating — in the form of conductive sheets, 3D plastic, or paint — is necessary. You can see a demonstration and many unique applications in the video below. They’ve even made a touch-sensitive brain out of Jell-O and a touchable snowman out of Play-Doh.

The concept is simple. Multiple electrodes surround the surface. The system injects a current using a pair of electrodes and then senses the output at the other terminals. A finger touch will change the output of several of the electrodes. Upon detection, the system will change the injection electrodes and repeat the sensing. By using multiple electrode pairs and tomography techniques, the system can determine the location of touch and even do rough motion tracking like a low-resolution touch pad mouse.

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Logic Analyzer on Chips

The Internet is full of low-speed logic analyzer designs that use a CPU. There are also quite a few FPGA-based designs. Both have advantages and disadvantages. FPGAs are fast and can handle lots of data at once. But CPUs often have more memory and it is simpler to perform I/O back to, say, a host computer. [Mohammad] sidestepped the choice. He built a logic analyzer that resides partly on an FPGA and partly on an ARM processor.

In fact, his rationale was to replace built-in FPGA logic analyzers like Chipscope and SignalTap. These are made to coexist with your FPGA design, but [Mohammad] found they had limitations. They also eat up die space you might want for your own design, so by necessity, they probably don’t have much memory.

The system can capture and display 32-bit signals on a 640×480 VGA monitor in real-time. The system also has a USB mouse interface which is used to zoom and scroll the display. You can see a video of the thing in operation, below.

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Arduino (and Camera) Take Amazing Pictures

There’s an old joke where you ask someone what’s the most important thing about comedy. When they get to about the word “important,” you interrupt them and say, “Timing!” Perhaps the same thing can be said for photography. [Ted Kinsman’s] students at the Rochester Institute of Technology would probably agree. They built an Arduino-based rig to do inexpensive stop action photography.

As Arduino projects go, it isn’t very sophisticated. The circuit contains a  sound detection module and an optoisolator. The code would easily fit on a piece of notebook paper. When a loud sound occurs, the Arduino triggers the flash. Simple enough, but the resulting pictures are amazing. It also looks like a lot of fun to destroy perfectly good things in the name of art.

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3D Printing Custom LED Bar Graphs

[BikerGlen] wanted to spice up his zombie containment unit (see video below) so he designed and 3D printed some very cool looking bar graphs. Apparently, you can get curved bar graph LEDs, but only if you buy a fairly large quantity. Hand soldering discrete LEDs at the perfect angle would be frustrating, but with a 3D printed jig, it was a piece of cake.

The devices use a MAX6954 LED driver, so it needs very few parts and takes commands via SPI. The chips were not cheap, but the small size and high integration sold [Glen] on it.

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Zen and the Art of Arduino

A zen garden should be a source of relaxation and escape from the everyday. The whole point should be to escape from–among other things–your electronics. Unless you are [MakrToolbox]. Then you’ll make a beautiful zen garden end table that allows you to make patterns in the sand using a ball bearing and an Arduino. You can see a video below.

Technically, the device is almost an upside down 3D printer with no Z axis. The mechanism moves a magnet which controls the steel ball and draws patterns in the sand. However, the really impressive parts of this project are the woodworking for the end table and the impressive documentation, should you want to reproduce this project yourself.

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