Apparently Time IS Money

April 13, 2017 by Al Williams 25 Comments

Some people like to tweak cars. Some like to overclock PCs. Then there are the guys like [Jack Zimmermann] who are obsessed with accurate time. He’s working on a project that will deploy NTP (Network Time Protocol) servers in different African countries and needed small, cheap, energy-efficient, and accurate servers. What he wound up with is a very accurate setup for around $200. Along the way, he built some custom hardware, and hacked a computer to sync to the GPS clock reference.

His original attempt was with a Raspberry Pi 3. However, the network adapter isn’t the fastest possible, both because it is 100 MBPS and, primarily, because it is connected via the USB bus. Network latency due to these limitations makes it difficult to serve accurate time.

His solution includes an Odroid C2. For $50 it is a very capable computer with four cores, gigabit Ethernet, and can even use eMMC storage which is faster than the usual SD card. You can still use a conventional SD card, though, if you prefer.

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Daedalus Jet Suit Takes To The Skies

April 13, 2017 by Adam Fabio 38 Comments

[Richard Browning] wants to fly like Daedalus. To us, it looks a bit more like Iron Man. [Browning] is working on project Daedalus, a flight suit powered by six jet engines. These turbines are exactly the type one would find on large, fast, and expensive R/C planes. Some of this is documented on his YouTube channel, Gravity Industries, though RedBull has also gotten involved and have a video of their own that you can check out after the break.

The project started last year in [Browning’s] garage. He strapped a jet to an old washing machine to test its thrust. The jet nearly flipped the machine over, so he knew he would have enough power to fly. The suit started with a turbine strapped to each arm. Then it became two on each arm. This was enough for moonlike hops, but not enough for actual flight. Strapping an engine to each leg worked but was rather hard to control. The current configuration features two turbines per arm, and two on a backpack.

The whole setup is quite similar to [Frank Zapata]’s Flyboard Air, with one key difference – [Browning] is supporting two thirds of his weight with his hands. The effect is similar to supporting oneself on gymnastic rings, which is part of his extreme physical training regimen.

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Measuring Tiny Masses Acoustically

April 13, 2017 by Dan Maloney 11 Comments

How do you measure the mass of something really, really tiny? Like fish-embryo tiny. There aren’t many scales with the sensitivity and the resolution to make meaningful measurements in the nanogram range, so you’ve got to turn to other methods, like measuring changes in the resonant frequency of a glass tube. And that turns out to be cheap and easy for the home gamer to reproduce.

In a recent scholarly paper, [William Grover] et al from the University of California Riverside outline the surprisingly simple and clever method of weighing zebrafish embryos, an important model organism used in all sorts of developmental biology and environmental research. [Grover]’s method is a scaled-up version of a suspended microchannel resonator (SMR), a microelectromechanical device that can measure the mass of single cells or even weigh a virus particle. Rather than etch the resonator out of silicon, a U-shaped glass tube is vibrated by a piezoelectric speaker and kept at its resonant frequency by feedback from a cheap photointerrupter. When an embryo is pumped into the tube, the slight change in mass alters the resonant frequency of the system, which is easily detected by the photointerrupter. The technique can even be leveraged to measure volume and density of the embryos, and all for about $12 in parts.

In the lab, [Grover]’s team uses a data acquisition card and LabVIEW to run the resonant loop, but there’s no reason a DIY version of this couldn’t use an Arduino. In fact, tipster [Douglas Miller] expects someone out there will try this, and would appreciate hearing the details. You can ping him on his hackaday.io page.

Hackaday Prize Entry: Zappotron Super Sequencer

April 13, 2017 by Jenny List 7 Comments

If you fancy a go at circuit bending, where do you start? Perhaps you find a discarded musical toy at a junk sale and have a poke around, maybe you find the timing circuit and pull it a little to produce a pitch bend. Add a few wires, see what interesting things you can do connecting point A to point B, that kind of thing.

Many of us have spent an entertaining afternoon playing in this way, though it’s probable few of us have achieved much of note. [Russell Kramer] however must have persevered to become a circuit bender par excellence, as his latest project is one of the most accomplished circuit bending projects we’ve seen.

Zappotron Super Sequencer is an analog sequencer. Except that sentence simply doesn’t convey what it really is, it’s an analog sequencer with four sound sources: two tape decks, a 4046 oscillator, and a circuit-bent spelling tutor toy, and its sequencer component is controlled with a Nintendo light gun and a CRT screen.

You might be thinking that you could do all that with relative ease on a modern single board computer, but what makes this project so special is that he’s achieved it using only logic chips and diode logic gates, not a microprocessor in sight save for the one in the spelling toy. The build log goes through all the circuitry in detail, and we have to tell you it’s a work of art that demonstrated his mastery of both analog circuitry and digital logic.

To cap it all off he’s mounted it in a gloriously retro console, complete with retro embossed labeling. This is a high-quality item that we’d suggest you take a while to read about in detail. He’s posted a video demonstration if you’d like to see it in action, we’ve posted it below the break.

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Heat Shrink Tubing And The Chemistry Behind Its Magic

April 13, 2017 by Dan Maloney 70 Comments

There’s a lot to be said in favor of getting kids involved in hacking as young as possible, but there is one thing about working in electronics that I believe is best left as a mystery until at least the teenage years — hide the shrink tube. Teach them to breadboard, have them learn resistor color codes and Ohm’s Law, and even teach them to solder. But don’t you dare let them near the heat shrink tubing. Foolishly reveal that magical stuff to kids, and if there’s a heat source anywhere nearby I guarantee they’ll blow through your entire stock of the expensive stuff the minute you turn your back. Ask me how I know.

I jest, but only partly. There really is something fun about applying heat shrink tubing, and there’s no denying how satisfying a termination can be when it’s hermetically sealed inside that little piece of inexplicably expensive tubing. But how does the stuff even work in the first place?

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FPGA Emulates NES Cart; Prototype So Cyberpunk

April 13, 2017 by Bryan Cockfield 25 Comments

By now, most of us have had some experience getting ROMs from classic video games to run on new hardware. Whether that’s just on a personal computer with the keyboard as a controller, or if it’s a more refined RetrioPie in a custom-built cabinet, it has become relatively mainstream. What isn’t mainstream, however, is building custom hardware that can run classic video games on the original console (translated). The finished project looks amazing, but the prototype blows us away with it’s beauty and complexity.

[phanick]’s project is a cartridge that is able to run games on the Polish Famicon clone called the Pegasus. The games are stored on an SD card but rather than run in an emulator, an FPGA loads the ROMs and presents the data through the normal edge-connector in the cartridge slot of the console. The game is played from the retro hardware itself. It takes a few seconds to load in each ROM, but after that the Pegasus can’t tell any difference between this and an original cartridge.

The original prototype shown here was built back in 2012. Since then it’s been through a few iterations that have reduced the size. PCBs were designed and built in-house, and the latest revision also includes a 3D-printed case that is closer to the size of the original Famicon cartridges.

Even if you don’t have an interest in classic video games or emulation, the video below is worth checking out. (Be sure to turn on the subtitles if you don’t speak Polish.) [phanick] has put in a huge amount of time getting all of the details exactly right, and the level of polish shows in the final product. In fact, we’ve featured him before for building his own Famicom clone.

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Say It With Me: Root-Mean-Square

April 13, 2017 by Elliot Williams 23 Comments

If you measure a DC voltage, and want to get some idea of how “big” it is over time, it’s pretty easy: just take a number of measurements and take the average. If you’re interested in the average power over the same timeframe, it’s likely to be pretty close (though not identical) to the same answer you’d get if you calculated the power using the average voltage instead of calculating instantaneous power and averaging. DC voltages don’t move around that much.

Try the same trick with an AC voltage, and you get zero, or something nearby. Why? With an AC waveform, the positive voltage excursions cancel out the negative ones. You’d get the same result if the flip were switched off. Clearly, a simple average isn’t capturing what we think of as “size” in an AC waveform; we need a new concept of “size”. Enter root-mean-square (RMS) voltage.

To calculate the RMS voltage, you take a number of voltage readings, square them, add them all together, and then divide by the number of entries in the average before taking the square root: $\sqrt{\frac{1}{n} \left(v_1^2 + v_2^2 +...+ v_n^2\right)}$ . The rationale behind this strange averaging procedure is that the resulting number can be used in calculating average power for AC waveforms through simple multiplication as you would for DC voltages. If that answer isn’t entirely satisfying to you, read on. Hopefully we’ll help it make a little more sense.