Solving The Mysteries Of Grounding While Improving A Power Supply

February 4, 2020 by Bryan Cockfield 22 Comments

Grounding problems and unwanted noise in electrical systems can often lead to insanity. It can seem like there’s no method to the madness when an electrical “gremlin” caused by one of these things pops its head out. When looking more closely, however, these issues have a way of becoming more obvious. In a recent video, [Fesz Electronics] shows us how to investigate some of these problems by looking at a small desktop power supply, modelling it in LTSpice, and reducing the noise on the power supply’s output.

While everything in this setup is properly grounded, including the power supply and oscilloscope, the way the grounding systems interact can contribute to the high amount of noise. This was discovered by isolating the power supply from earth ground using electrical tape (not recommended as a long-term solution) and seeing that the noise was reduced. However, the ripple increased substantially, so a more permanent fix was needed. For that, the power supply was modelled in LTSpice. This is where a key discovery was made: since all the parts of the power supply aren’t ideal, noise can be introduced from the actual real-life electrical behavior of some of the parts. In this case, it was non-ideal capacitance in the transformer.

According to the model, this power supply could be improved by adding a larger capacitor across the output leads, and also by increasing their inductance. A large capacitor was soldered in the power supply and an iron ferrule was added, which decreased the noise level from 100 mV to around 20. Still not perfect, but a much needed improvement to the simple power supply. If, on the other hand, you want to make sure you eliminate that transformer’s capacitance completely, you can always go with a transformerless power supply. That carries other risks, though.

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Hoverboard Grows Up, Becomes Magnetic Drill Press

February 4, 2020 by Kristina Panos 11 Comments

If you need to drill metal in tight places, the magnetic drill press, or mag drill is your BFF. The idea here is that a drill press with an electromagnetic base can go anywhere, and even drill horizontally if need be. If you don’t need to use one often, but want one anyway, why not build one out of e-waste?

[DIY KING 00] built this mag drill starting with the motor from a hoverboard. While these three-phase brushless motors have a lot of torque to offer reuse projects like this, they’re not designed to be particularly fast.

He was able to make it about three times faster by cutting the windings apart and reconnecting them in parallel instead of series. He designed a simple PCB to neatly tie all the connections back together and added an electronic speed control (ESC) from an R/C car.

Reluctant to give up the crown, he made his own three-coil electromagnetic base, using a drill to wind magnet wire around temporary chuck-able cores. The coils are then potted in epoxy to keep out dust and drilling debris. Everything runs from two large LiPo batteries, and he can get about 15 minutes of high-torque drilling done before they’re dead. Can you feel the electromagnet pulling you past the break to check out the build and demo video?

Depending on what you’re doing, you might get away with a magnetic vise instead.

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China X86 Chips Hitting The Market

February 4, 2020 by Al Williams 99 Comments

Last year, fabless chip maker Zhaoxin announced they were readying a multicore x86-compatible CPU. According to media reports, the chips are showing up on Chinese marketplaces like Taobao shipping around March.

The company is a joint venture between the Shanghai Municipal Government and VIA Technologies, a familiar name in the PC business. It makes even more sense if you remember that VIA bought Centaur who had built simple x86 chips and used the simplicity to add more cache that more complex Intel and AMD chips. These fell out of the hobby market, but they’ve still been pushing forward providing simple designs that are inexpensive and consume low power.

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Florence Nightingale: The Lady With The Data

February 4, 2020 by Kristina Panos 15 Comments

When you think of Florence Nightingale, you probably imagine a nurse with a lamp, comforting soldiers. Indeed, Florence is considered the mother of modern nursing. But she also made serious contributions in statistical data analysis, and used the diagram named after her, the Nightingale rose diagram, to convince the British Parliament to enact sanitation reforms that saved hundreds of thousands, if not millions, of lives.

During the Crimean war, Florence worked around the clock as head nurse in an overcrowded field hospital. But she also found time to create graphs to illustrate the terrible conditions of that field hospital to members of British Parliament. The sanitation reforms she led greatly improved the life of the soldiers in battle, and widespread adoption of her hygienic practices vastly reduced mortality rates of humanity in general.

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Nifty Soundbender Built From EBay Modules

February 4, 2020 by Lewin Day 5 Comments

Custom audio greeting cards are a trifling gimmick, and a hefty investment compared to their paper-based colleagues. However, the technology inside can be twisted and hacked towards more interesting ends, as [lonesoulsurfer] demonstrates with his sound-bending build.

Rather then go to the trouble and expense of gutting a greeting card, [lonesoulsurfer] simply purchases the sound recording module off eBay which often turns out cheaper anyway. It’s hacked with a couple extra buttons and a speed control, and then wired up with a reverb module that itself gets tweaked to add an echo mode. It’s all bundled up with a speaker and microphone and installed in a case that formerly held an ignition tuning analyzer from the 1970s.

The final result is quite handsome, with a wooden panel holding the speaker and a smattering of knobs, buttons, and switches to play with. After recording an audio sample, it’s possible to speed it up, slow it down, and add echo and reverb until you’re left with something unrecognizable and weird. We’ve actually seen similar projects before, like this author’s first ever article for these hallowed pages. Video after the break.

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How To Hack A Portable Bluetooth Speaker By Skipping The Bluetooth

February 4, 2020 by Roger Cheng 54 Comments

Portable Bluetooth speakers have joined the club of ubiquitous personal electronics. What was once an expensive luxury is now widely accessible thanks to a prolific landscape of manufacturers mass producing speakers to fit every taste and budget. Some have even become branded promotional giveaway items. As a consequence, nowadays it’s not unusual to have a small collection of them, a fertile field for hacking.

But many surplus speakers are put on a shelf for “do something with it later” only to collect dust. Our main obstacle is a side effect of market diversity: with so many different speakers, a hack posted for one speaker wouldn’t apply to another. Some speakers are amenable to custom firmware, but only a small minority have attracted a software development community. It doesn’t help that most Bluetooth audio modules are opaque, their development toolchains difficult to obtain.

So what if we just take advantage of the best parts of these speakers: great audio fidelity, portability, and the polished look of a consumer good, to serves as the host for our own audio-based hacks. Let’s throw the Bluetooth overboard but embrace all those other things. Now hacking these boxes just requires a change of mindset and a little detective work. I’ll show you how to drop an Arduino into a cheap speaker as the blueprint for your own audio adventures.

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Slice Through Your Problems With A Shukran

February 4, 2020 by Kerry Scharfglass 38 Comments

We’d wager most hackers are familiar with FTDI as the manufacturer of the gold standard USB-UART interfaces. Before parts like the ultra cheap CH340 and CP2102 became common, if you needed to turn a USB cable into a TTL UART device, “an FTDI” (probably an FT232RL) was the way to make that happen. But some of the parts in the FT232* family are capable of much more. Wanting to get at more than a UART, [linker3000] designed the Shukran to unlock the full potential of the FT232H.

The FT232H is interesting because it’s an exceptionally general purpose interface device. Depending on configuration it can turn USB into UART, JTAG, SPI, I2C, and GPIO. Want to prototype the driver for a new sensor? Why bother flashing your Teensy when you can drive it directly from the development machine with an FT232H and the appropriate libraries?

The Shukran is actually a breakout for the “CJMCU FT232H” module available from many fine internet retailers. This board is a breakout that exposes a USB-A connecter on one side and standard 0.1″ headers on the other, with a QFN FT232H and all the passives in the middle. But bare 0.1″ headers (in a square!) require either further breadboarding or a nest of jumper wires to be useful. Enter the Shukran. In this arrangement, the CJMCU board is cheap and handles the SMT components, and the Shukran is easy to assemble and makes it simple to use.

The Shukran gives you LEDs, buttons and switches, and a bunch of pull up resistors (for instance, for I2C) on nicely grouped and labeled headers. But most importantly it provides a fused power supply. Ever killed the USB controller in your computer because you forgot to inline a sacrificial USB hub? This fuse should take care of that risk. If you’re interested in building one of these handy tools, sources and detailed BOM as well as usage instructions are available in the GitHub repo linked at the top.