Piezoelectric Gyro Shows How They Rolled Back In The Day

February 7, 2019 by Dan Maloney 4 Comments

There’s no doubting the wonders that micro-electromechanical systems (MEMS) technology have brought to the world. With MEMS chips, your phone can detect the slightest movement, turning it into a sensitive sensor platform that can almost anticipate what you’re going to do next. Actually, it’s kind of creepy when you think about it.

But before nano-scale MEMS inertial sensing came along, lots of products needed to know their ups from their downs, and many turned to products such as this vibrating piezoelectric gyroscope that [Kerry Wong] found in an old camcorder. The video below shows a teardown of the sensor, huge by MEMS standards but still a marvel of micro-engineering. The device is classified as a Coriolis vibratory gyroscope (CVG) which, as the name implies, uses the Coriolis effect to sense rotation. In this device, [Kerry] found that a long, narrow piezoelectric element spans the long axis of the sensor, suspended from what appears to be four flexible arms. [Kerry] probed the innards of the sensor while powered up and discovered a 22 kHz signal on the piezo element; this vibrates the bar in one plane so that when it rotates, it exerts a force on the support arms that can be detected. Indeed, [Kerry] hooked the output of the sensor to a wonderfully old-school VOM whose needle wiggled with the slightest movement of the sensor.

Sadly, MEMS made this kind of sensor obsolete, but we appreciate the look under the hood. And really, MEMS chips are using the same principle to detect motion, just on a much smaller scale. Want the MEMS basics? [Al] has you covered.

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Open Source LIDAR Lets You Get Down To The Nitty Gritty

February 6, 2019 by Lewin Day 11 Comments

If you’re unfamiliar with LIDAR, you might have noticed it sounds a bit like radar. That’s no accident – LIDAR is a backronym standing for “light detection and ranging”, the word having initially been created as a combination of “light” and “radar”. The average person is most likely to have come into contact with LIDAR at the business end of a police speed trap, but it doesn’t have to be that way. Unruly is the open source LIDAR project you’ve been waiting for all along.

Unlike a lot of starter projects, LIDAR isn’t something you get into with a couple of salvaged LEDs and an Arduino Uno. We’re talking about measuring the time it takes light to travel relatively short distances, so plenty of specialised components are required. There’s a pulsed laser diode, and a special hypersensitive avalanche photodiode that operates at up to 130 V. These are combined with precision lenses and filters to ensure operation at the maximum range possible. Given that light can travel 300,000 km in a second, to get any usable resolution, a microcontroller alone simply isn’t fast enough to cut it here. A specialized time-to-digital converter (TDC) is used to time how long it takes the light pulse to return from a distant object. Unruly’s current usable resolution is somewhere in the ballpark of 10 mm – an impressive feat.

It’s a complicated project, requiring the utmost attention to detail to get any results at all. The team behind Unruly have done a great job of both designing and documenting the project. It’s great to see an open source LIDAR package in the wild, giving hackers more options than just the pre-baked commercial modules on the market. We can’t wait to see where the project goes next.

For more on LIDAR, check out last week’s Hackaday podcast – we cover Unruly, as well as a handful of other standout projects in the field.

Fail Of The Week: Electromigration Nearly Killed This Xerox Alto

February 3, 2019 by Jenny List 51 Comments

The Living Computers museum in Seattle has a Xerox Alto, the machine famous for being the first to sport a mouse-based windowing graphical user interface. They received it in working condition and put it in their exhibit, but were dismayed when a year later it ceased to operate. Some detective work revealed that the power supply was failing to reach parts of the machine, and further investigation revealed an unlikely culprit. Electromigration had degraded the contacts between the supply pins and the backplane traces.

If electromigration is new to you, don’t feel ashamed, it was a new one to us too. It’s “the transport of material caused by the gradual movement of the ions in a conductor due to the momentum transfer between conducting electrons and diffusing metal atoms“, got it? Okay, that’s just a long way to say that passing a sufficiently high current through a conductor for a long time can physically move the metal of that conductor.

This one just doesn’t pop up very often. But in the case of the Alto, an under-specified power distribution system caused a lot of current to flow through too few solder joints. Those joints were left without enough metal to make a decent connection, so they failed.

The fix came with a set of sturdy busbars freshly soldered to the pins, but the interest in this piece comes more from the unusual phenomenon that caused it. That soldered joints can seemingly flow away defies belief. It’s still something most of us will never encounter, but like tales of ball lightning it’s one for the “Fancy that!” collection.

We’ve covered the Alto before, most notably [Ken Shirriff]’s work in restoring the Computer History Museum’s example.

Blacksmith Elevates The Craft With This Fabulous Strongbox

February 3, 2019 by Dan Maloney 35 Comments

For most of human industrial history, the blacksmith was the indispensable artisan. He could fashion almost anything needed, from a simple hand tool to a mechanism as complex as a rifle. Starting with the most basic materials, a hot forge, and a few tools that he invariably made himself, the blacksmith was a marvel of fabrication.

If you have any doubt how refined the blacksmith’s craft can be, feast your eyes on [Seth Gould]’s masterpiece of metalwork. Simply called “Coffer”, [Seth] spent two years crafting the strongbox from iron, steel, and brass. The beautifully filmed video below shows snippets of the making, but we could easily watch a feature-length film detailing every aspect of the build. The box is modeled after the strongboxes built for the rich between the 17th and 19th centuries, which tended to favor complex locking mechanisms that provided a measure of security by obfuscation. At the end of the video below, [Seth] goes through the steps needed to unlock the chest, each of which is filled with satisfying clicks and clunks as the mechanism progresses toward unlocking. The final reveal is stunning, and shows how much can be accomplished with a forge, some files, and a whole lot of talent.

If you’ve never explored the blacksmith’s art before, now’s the time. You can even get started easily at home; [Bil Herd] will show you how.

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Microwave Parts Become Quick And Nasty Jacob’s Ladder

February 2, 2019 by Lewin Day 20 Comments

The Jacob’s Ladder is an electrical device named after a biblical “ladder to Heaven”, consisting of a pair of vertically oriented conductors that spread apart vertically. These conductors are charged with high voltage, which creates the repeatedly climbing arc we’ve all come to know and love from science fiction movies of yesteryear.

[LOOK MUM NO COMPUTER] was on a scavenger hunt for electronic junk, and came across a microwave in a skip that was begging to be hacked. After kicking around a few ideas, it was decided that the microwave would donate its high voltage transformer to create a Jacob’s ladder. The transformer is first bolted down to a piece of wood, and creates some sparks on the bench when shorted. The output is then wired to a pair of copper pipes to create the classic effect.

Unfortunately, the device isn’t self starting, requiring the electrodes to be temporarily short circuited to generate the initial arc. We suspect that increasing the voltage may help things somewhat, either with another transformer in series or with a voltage multiplier.

It goes without saying that high voltage projects do bring certain risks to life and limb that should not be overlooked. If you’ve still got a thirst for danger, check out this home built X-ray machine. Video after the break.

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The Craziest Live Soldering Demo Is The Cyborg Ring

February 1, 2019 by Mike Szczys 9 Comments

You can define the word crazy in myriad ways. Some would say using SMD resistors and QFN microcontrollers as structural elements is crazy. Some would say hand soldering QFN is crazy, much less trying to do it on edge rather than in the orientation the footprint is designed for. And of course doing it live on stage in front of people who eat flux for breakfast is just bonkers. But Zach did it anyway and I’m delighted he did.

This is the cyborg ring, and it’s a one-of-a-kind leap in imagination — the kind of leap people have come to expect from Zach Fredin who modeled neurons on PCBs, depopulated an SMD LED matrix and airwired it, and replaced his ThinkPad fingerprint reader with an ARM debugger port. The construction leverages the precise nature of manufactured parts: the ATtiny85 that drives the ring is exactly twice the width of an 0805 component. This means he can bridge the two circuit boards that make up the ring with the QFN microcontroller, and then use two 10M Ohm resistors as structural spacers in a few places around the ring. The jewels in this gem of a project are red LEDs that can be addressed in an animated pattern.

There’s an adage that all live talk demos are doomed to fail, and indeed the uC in this project doesn’t want to speak to the programmer at the end of the 9-minute exhibition. But Zach did manage to solder the two halves on the ring together live on stage, and it’s worth enduring the camera issues and low starting volume at the start of this livestream to watch him perform some crazy magic. Good on you Zach for putting yourself out there and showing everyone that there’s more than one way to stack resistors.

If this demo leaves you wanting to hear more of what Zach’s adventures, we recommend checking out his 2016 Supercon talk on the Neurobytes development and manufacturing process.

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This Chromecast Volume Knob Has A Certain ’70s Chic

January 31, 2019 by Lewin Day 10 Comments

Chromecast devices have become popular in homes around the world in the last few years. They make it easy to cast audio or video from a smartphone or laptop, to a set of speakers or a display connected to the same network. [Akos] wanted to control the volume on these devices with a single, simple piece of equipment, rather than always reaching for a smartphone. Thus was built the CastVolumeKnob.

The project began by using Wireshark to capture data sent by the pychromecast library. Once [Akos] understood the messaging format, this was implemented in MicroPython on an ESP8266. A rotary encoder is used as a volume knob, and a Neopixel ring is used for visual feedback as to the device being controlled and the current volume level.

Further work was done to improve usability, with an ATtiny85 microcontroller being used to monitor the encoder for button presses before waking up the ESP8266, greatly reducing power consumption. The device is also rechargeable, thanks to an 18650 lithium polymer battery, and charger and boost converter boards. It’s all wrapped up in a sleek 3D printed case, with a translucent bezel for the LEDs and a swanky machined aluminium knob as the cherry on top.

It’s a homemade device that nonetheless would be stylish and unobtrusive in the living room environment. We imagine it proves very useful when important phone calls come in and it’s necessary to cut the stereo down to a more appropriate volume.

For another take, check out this USB volume knob with a nice weighty feel, courtesy of lead shot.