The Grid Dip Meter: Forgotten Instrument

November 30, 2015 by 74 Comments

It used to be a major rite of passage for a hardware hacker to acquire an oscilloscope. Until recently, new instruments were rarely in normal people’s budgets, so you probably made do with a used scope. Now, there are lots of inexpensive options, especially if you include low-end PC scopes and “scope meters.” Digital meters are also now inexpensive (often free at some major stores), along with signal generators, frequency counters, and even logic analyzers.

But there is one piece of test equipment you don’t see as often as you used to and its a shame, because it is a very versatile piece of kit. Admittedly, if you aren’t doing wireless work, it might not be high on your wish list, but if you do anything with RF, it is not only a versatile tool, but a good value, too. What’s it called? That depends. Historically, they went by the name “Grid Dip Oscillator” or GDO. Sometimes you’d hear it called a “Grid Dip Meter” instead. However, modern versions don’t have tubes (and, thus, no grid) so sometimes you hear them now called dip meters or maybe just dippers.

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1Wamp, An Open Hardware Guitar Amplifier

November 30, 2015 by 26 Comments

The folks at [ElectroSmash] recently released 1Wamp – a one watt, open hardware, Guitar amplifier packed with features. It consists of a JFET based pre-amplifier, a Big Muff Pi a.k.a BMP based Tone control and an LM386 power amplifier. The dual JFET pre-amp provides tube-like sound, the BMP provides a nice tonal range while the LM386 can drive various types of output’s ranging from headphones to speaker cabinets.

1Wamp had controls for Tone, Volume and Gain, a Speaker/Cabinet output, a headphone output with an integrated attenuator switch and an aux. input. The aux. input is handy as it adds any line level input signal to the guitar sound, allowing you to practice with metronome or MP3 backing tracks or drum bases. It runs off either a 9V battery or can be powered via an external power source. [ElectroSmash] have released all the native KiCad design files. If you’d like a quick look at the design, check out the Schematic PDF and the Bill of Materials. There’s also a handy assembly manual [PDF] that shows how to build it in five easy steps.

Their blog post provides extremely detailed circuit analysis of every part of the design, starting from the power supply filter to remove mains “hum” all the way through to PCB layout considerations for noise reduction. Oscilloscope screen shots provide signal analysis showing bias points and signal levels throughout the circuit. The choice of value for every component is explained, along with the consequences of changing those values. This makes it easy to customise the 1Wamp to suit individual tastes. We also noticed SPICE models for the recommended and alternative JFET transistors, in case you need to customise the design by changing component values.

There’s also a lot of audio amplifier trivia, references and links shared in their post. This includes a detailed analysis of the LM386 op-amp. Want to add some bling to your 1Wamp build? There are a lot of handy tips on how to add cool LED lighting to the amplifier if it is mounted in a standard metal enclosure. However, the PCB has some really nice graphics, so an acrylic-sandwich-type enclosures look best. Check out the video that walks through the features of the 1Wamp and shows off its performance. And while on the subject of Audio electronics, here’s one of their earlier projects – an open source Arduino guitar pedal.

Documentation to this level proves several things, most notably a love for this design and deep consideration for those who will use and modify this amplifier. It’s a great pattern to follow with your own Open Source designs.

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Swallow The Doctor — The Present And Future Of Robots Inside Us

November 30, 2015 by 7 Comments

I recently finished the Silo series by Hugh Howey, a self-published collection of novellas that details life in a near-future, post-apocalyptic world where all that remains of humanity has been stuffed into subterranean silos. It has a great plot with some fun twists and plenty of details to keep the hacker and sci-fi fan entertained.

One such detail is nanorobots, used in later volumes of the series as both life-extending tools and viciously specific bio-weapons. Like all good reads, Silo is mainly character driven, so Howey doesn’t spend a lot of eInk on describing these microscopic machines – just enough detail to move the plot along. But it left me wondering about the potential for nanorobotics, and where we are today with the field that dates back to Richard Feynman’s suggestion that humans would some day “swallow the doctor” in a 1959 lecture and essay called “There’s Plenty of Room at the Bottom.”

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A Robotic Wheatley Replica created by Evie Bee

Robotic Wheatley From Portal 2

November 30, 2015 by 7 Comments

It’s been over 4 years since Portal 2 launched, but Wheatley, the AI character with a British accent, remains a captivating character. [Evie Bee] built a Wheatley replica complete with sound, movement, and one glowing eye.

The body of Wheatley is made out of blue insulation foam, also called XPS foam, laminated together with UHU Polyurethane glue. This formed a sphere, which was then cut into a detailed body. Papier mache clay was used to strengthen the thin foam.

The electronics for this build provide light, motion, and sound. The eye is moved by a total of 3 Arduino controlled servos: two for the movement of the eye, and one to allow it to open and close. Movement is controlled by two joysticks. Sound is provided by the Adafruit Sound Board, which connects to a speaker and a Velleman Sound to Light Kit. This kit controls the LEDs that light the eye, making it react to the voice of Wheatley.

You can watch this Wheatley rant at you after the break. Of course if you’re going to have a Wheatley you need a GLaDOS potato as well.

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Listen Up: IPhone Hack Diagnoses HVAC

November 30, 2015 by 29 Comments

We all know that guy (or, in some cases, we are that guy) that can listen to a car running and say something like, “Yep. Needs a lifter adjustment.” A startup company named Augury aims to replace that skill with an iPhone app.

Aimed at commercial installations, a technician places a magnetic sensor to the body of the machine in question. The sensor connects to a custom box called an Auguscope that collects vibration and ultrasonic data and forwards it via the iPhone to a back end server for analysis. Moving the sensor can even allow the back end to determine the location of the fault in some cases. The comparison data the back end uses includes reference data on similar machines as well as historical data about the machine in question.

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RasPi LED Panel Library Is Nyan-tastic

November 29, 2015 by 5 Comments

Quick–in a pinch, let’s have ourselves a giant RGB LED Matrix! As marvelous as it sounds, it’s pretty easy to forget that there’s a battle to be won against picking the right parts, debugging drivers, and sorting out our spaghetti wiring. Rest assured, [Hzeller] has done all of the heavy-lifting for us with a Raspberry Pi RGB LED Matrix Implementation that scales to multiple panels and runs on any Pi model to date!

Offering 24-bit color at about 100 Hz for up to a grand total of 36 panels, [Hzeller’s] library is no slouch. The library enables customization of your panel arrangements, and a separate project (also [Hzeller’s] handiwork) makes this setup compatible with the pixel-pusher protocol as a network device.

It’s certainly true that many of us have a thing for these displays, so you might ask: “have we seen this before? What’s all the fuss?” Like the others, the final product is a sight to behold, but [hzeller] and his implementation stands strong because of his phenomenal response to answering the question: how? In fact, almost more impressive is his comprehensive online documentation. Inside, [hzeller] details various hardware configurations for a custom number of panels or a particular flavor of Pi that drives them. He also provides references for pinout quirks and provides out-of-the-box software demos to ensure that anyone can bring this project to life. If a poorly-written or non-existent READMEs have made you shy away from building on an open-source project, fear not. From pinout quirks and out-of-the-box software demos, [hzeller] has covered all the bases and given us a project that folks of all levels of hacking.

Perhaps the best part of this project is the span of the audience that can take something away from it. If you’re a seasoned Linux junkie, dive into the source code to get a good feel of mechanics of how [hzeller] pushes this project onto a single core in a Raspi-2 configuration. If you’re new to digital electronics, let this project be your moment to pick up a Pi, a panel (or four), and run, knowing that [hzeller’s] README is the only tome you’ll need to light up the night.

We had the honor of soaking up some Nyan-Cat rainbows with a live demo at this year’s SuperCon.

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Automated Picasso Coming To A Ceiling Near You

November 29, 2015 by 3 Comments

It’s not a day too late to switch your career from engineering to art or vice-versa! While some of us tend far towards one end or the other, some like [Chris] show us just how cool it is to walk the line… er, ceiling in this case. [Chris] took a cue from his fiancée’s latest mural project to create an automated painting jig he calls ARTbOT.

Spraying the ceiling with ARTbOT sounds like fun, but it’s a dream [Chris] needed to realize with only his spare time and small budget. Constraints aside, he’s pulled it off elegantly with a cluster of extruded aluminum tubing, a few paint sprayers, and a LabView-driven Fet triggered by encoder ticks on the drop wheel. To pain the image, it’s first binarized and scaled to accommodate ARTbOT’s 8-inch pixel size. ARTbOT then gets a boost from a scissor-lift where it can then track it’s linear position with the drop wheel to spray the pixel-pattern correctly.

[Chris] pulled this rig together to help his fiancée and her art company tackle huge canvases, in this case, large freeway underpasses. With preliminary studio tests running smoothly with ARTbOT proudly printing its name, we can’t wait to see the final piece. In the meantime, have a look at this edgy handheld alternative. Watch out mural artists! There’s an 8-bit contender in the ring these days.

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