Retrotechtacular: The Omega Navigational System

July 8, 2015 by Kristina Panos 7 Comments

In 1971, the United States Navy launched the Omega navigational system for submarines and surface ships. The system used radio frequencies and phase difference calculations to determine global position. A network of eight (VLF) transmitter sites spread around the globe made up the system, which required the cooperation of six other nations.

Omega’s fix accuracy was somewhere between one and two nautical miles. Her eight transmitter stations were positioned around the Earth such that any single point on the planet could receive a usable signal from at least five stations. All of the transmitters were synchronized to a Cesium clock and emitted signals on a time-shared schedule.

A ship’s receiving equipment performed navigation by comparing the phase difference between detected signals. This calculation was based around “lanes” that served to divvy up the distance between stations into equal divisions. A grid of these lanes formed by eight stations’ worth of overlapping signals provides intersecting lines of position (LOP) that give the sailor his fix.

In order for the lane numbers to have meaning, the sailor has to dial in his starting lane number in port based on the maps. He would then select the pair of stations nearest him, which were designated with the letters A to H. He would consult the skywave correction tables and make small adjustments for atmospheric conditions and other variances. Finally, he would set his lane number manually and set sail.

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Hackaday Links: July 5, 2015

July 5, 2015 by Brian Benchoff 28 Comments

It’s the fifth of July. What should that mean? Videos on YouTube of quadcopters flying into fireworks displays. Surprisingly, there are none. If you find one, put it up in the comments.

The original PlayStation was a Nintendo/Sony collaboration. This week, some random dude found a prototype in his attic. People were offering him tens of thousands of dollars on the reddit thread, while smarter people said he should lend it to MAME and homebrewer/reverse engineer groups. This was called out as a fake by [Vadu Amka], one of the Internet’s highly skilled console modders. This statement was sort of semi retracted. There’s a lot of bromide staining on that Nintendo PlayStation, though, and if it’s a fake, the faker deserves thousands of dollars. Now just dump the ROMs and reverse engineer the thing.

Remember BattleBots? It’s back. These are my impressions of the first two episodes: Flamethrowers are relatively common now, ‘parasitic bots’ – small, auxilliary bots fighting alongside the ‘main’ bot are now allowed. KOs only count for the ‘main’ bot. Give it a few more seasons and every bot will be a wedge. One of the hosts is an UFC fighter, which is weird, but not as weird as actually knowing some of the people competing.

Ceci n’est pas un Arduino, which means it’s from the SRL camp. No, wait. It’s a crowdfunding campaign for AS200 Industries in Providence, RI.

Wanna look incredibly sketchy? Weld (or braze, or solder) your keys to a screwdriver.

The UK’s National Museum of Computing is looking for some people to help maintain 80 BBC Micros. The museum has a ‘classroom’ of BBC micro computers still in operation. Caps dry out, switching power supplies fail, and over the years these computers start to die. If you have the skills and want to volunteer, give it a shot.

USA-made Arduinos are now shipping. That’s the Massimo Arduino, by the way.

Win $1000 for pressing a button. We’re gauranteed to give away a thousand dollar gift card for the Hackaday store next Wednesday to someone who has participated in the latest round of community voting for the Hackaday Prize.

Caption CERN Contest – Cut The Black Wire

July 4, 2015 by Adam Fabio 13 Comments

Week 21 of the Caption CERN Contest is now history. It’s been a great week of captions, so as always a huge thank you goes out to everyone who entered. We still have no idea what these two CERN scientists were working on. Lenses, switches, and a giant glass screen which could have anything behind it. It’s a tough one. But what we lack in facts, you all made up for in humor.

The Funnies:

“I spy with my quantum eye, something with a 75% probability of being spin up!”- [bbarrett90]
“Preping the Voight-Kampff set up, they have learnt from their unfortunately predecessors that a mirrored bullet proof glass between them and the upset replicant subject might be a good idea.” -[K.C. Lee]
“Mary and Steve swore that they were going to be the ones to win this year’s where’s Waldo competition, unfortunately they lost to the guys in the next lab with an SEM.” – [TrollinTeemo]

This week’s winner is [Lou] with “CERNs early attempts at a retina scanner were a bit cumbersome and time consuming. You had to get to work 20 minutes early just to get past the security check.” Lou’s bio is “Test engineer with Mechanical background who likes to tear things apart”. We bet he’s going to enjoy using his new Teensy 3.1 from The Hackaday Store to build something new with all the parts he has left over from teardowns!

Week 22

Holy cable gore, Batman! This image may make a network engineer or IT person weep, but it was business as usual back in the early days of CERN. 14 racks of equipment, with coaxial cables running everywhere. Let’s hope all those patches are connected to the correct ports! What were these two CERN scientists working on? It’s up to you to tell us as CERN has lost the records!

While you’re working on your captions, check out the old oscilloscope the standing scientist is using. Scope carts used to be necessary. Today all but the most powerful oscilloscopes weigh in at under 10 pounds.

This week’s prize is a Stickvise from The Hackaday Store. Add your humorous caption as a comment to this project log. Make sure you’re commenting on the contest log, not on the contest itself. As always, if you actually have information about the image or the people in it, let CERN know on the original image discussion page.

Good Luck!

Hacklet 54 – Virtual Reality Projects

July 3, 2015 by Adam Fabio 4 Comments

Virtual Reality is finally coming of age. Hackers, Makers and Engineers have dreamed of creating immersive interfaces for years. From the first flight simulators to today’s cellphone powered head mounted displays, VR has always been an exciting field. Many of the advances today are being created by hackers who were inspired by systems like Virtuality from the early 1990’s. Now 25 years on, we’re seeing amazing advances – not only in commercial systems, but in open source VR projects. This week’s Hacklet is all about the best VR projects on Hackaday.io!

We start with [j0nno] and D.I.Y Virtual Reality. [J0nno] has become interested in VR, and decided to build his own head mounted display. His goal is to create a setup with full head tracking and an open source software stack. He’s hoping to do this within a budget of just $200 AUD. [J0nno] started with the Ritech3d-V2 VR Goggles, which are a plastic implementation of Google’s project cardboard. For display he’s using a 5.6 inch 1280 x 800 TFT LCD. Tracking is optical, using IR LEDs and a PS3 Eye camera. [J0nno’s] background is in software, so he’s doing great setting up OpenVR and Perception. The hardware side is a bit new to him. This isn’t stopping [J0nno] though! In true hacker spirit, he’s learning all about resistors and driving LEDs as he works on D.I.Y Virtual Reality.

Next up is [Josh Lindsay] with Digitabulum: The last motion-capture glove. Digitabulum is a motion capture glove designed to be able to emulate most other motion capture systems. It is also designed to be relatively low-cost. At $400 per hand, it is less expensive than most other offerings, though we’d still love to see something even cheaper. [Josh] is going with inertial sensors, and a lot of them. Specifically he’s using no less than 17 LSM9DS1 Inertial Measurement Unit (IMU) sensors from ST Microelectronics. IMU sensors like this combine multiple rate gyros, accelerometers, and magnetometers into a single unit. Essentially every segment of every finger has its own sensor suite. As you might imagine, that is quite a bit of data to crunch. An Altera Max II CPLD and an ST Arm processor help boil down the data to something which a VR engine can process. [Josh] has been working on this project for over a year now, and he’s making great progress. The prototype glove looks terrific!

[Thomas] brings augmented reality to the table with Oculus Rift featured Crane control. What started as a hobby experiment became [Thomas’] major project at university. He’s connected an Oculus Rift to a toy crane. A stereo camera on the crane sends a video image to the operator. The camera is mounted on a pan/tilt mechanism driven by the Rift’s head tracking unit. Simple joystick controls allow [Thomas] to move the boom and lower the line. On-screen displays show the current status of the crane. The use of the Rift makes this an immersive demonstration. One could easily see how moving this system into the real world would make crane operations safer for crane operators.

Finally we have [Arcadia Labs] with DIY Augmented Reality Device. This project, which is the [Arcadia Labs] entry in the 2015 Hackaday Prize, uses two 320 x 240 screens to create an augmented reality head mounted display. While the resolution can’t match that of the Oculus Rift or HTC Vive, [Arcadia Labs] is ok with that. They’re going for a lower cost open source alternative for augmented reality. Tracking is achieved with an IMU, while a PS3 Eye camera provides the video. A Raspberry Pi controls the show. [Arcadia Labs] was able to get 50 frames per second on the displays just using the Pi’s SPI interface, however the USB PS3 Eye camera limits things to around 10 FPS. This project is under heavy development right now, so follow along with us to see where [Arcadia Labs] ends up!

If you want VR goodness, check out our new virtual reality projects list! Did I miss your project? Don’t be shy, just drop me a message on Hackaday.io. If you’re on the left coast of the USA, check out SOCAL Virtual Reality Conference and Expo. Hackaday is a sponsor. The event happens on July 12 at the University of California Irvine.

That’s it for this week’s Hacklet, As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

New Part Day: Memristors

July 2, 2015 by Brian Benchoff 61 Comments

For the last few years, the people in the know have been wondering about the memristor. The simplest explanation of what a memristor is comes from the name itself – it’s a memory resistor. In practice it’s a little more complex, but this basic understanding is enough to convey the fact that it’s a resistor that changes its resistance based on how much current has gone through it. The memristor was first described in the 70s by [Leon Chua], the idea sat in journals for nearly forty years, and in 2008 a working memristor was created by HP Labs.

Now you can buy one. Actually, you can buy eight in a 16-pin DIP package. It will, reportedly, cost $240 for the 16-pin DIP. That’s only $30 per memristor, and it’s the first time you can buy them.

These memristors are based on a silver chalcogenide (Ge2Se3). When a circuit ‘writes’ to this memristor and applies a positive voltage, silver ion migrate to the chalcogenide, forming what the datasheet (PDF) calls dendrites. This lowers the resistance of the memristor. When a negative voltage is applied to the device, these dendrites are removed, the memristor is ‘erased’, and the memristor returns to a high-resistance state.

This silver chalcogenide memristor is different from the titanium oxide memristors developed by HP Labs that is most frequently cited when it comes to this forgotten circuit element. This work is from [Kristy Campbell] of Boise State University. She’s been working on it for more than a decade now, with IEEE publications, conference proceedings (that one’s full text), and dozens of patents.

As far as applications for memristors go, there are generally two schools of thought on that. The most interesting, in terms of current computer technology, is storage. Memristors can hold either a binary 0 or a 1 in a fraction of the space NAND Flash or old-fashioned magnetic hard drives ever will. That means greater storage density, and bigger capacity hard drives with lower power requirements. These memristors have a limit of how many times they can be cycled – ‘greater than 2000 times’ according to the datasheet. That’s nearly an order of magnitude less than MLC Flash, and something wear leveling can’t reasonably compensate for. This is a new technology, though, so that could change.

The second major expected use for memristors is neural nets. Neural nets are just a series of inputs, a few neurons, outputs, and connections between all three. These connections are weighted, and the variable resistance of memristors puts them in a unique position to emulate in hardware at the most basic level what was once done with software and custom ASICs. The trade name for these memristors – Neuro-Bit – and the company name – Bio Inspired Technologies – give you a clue at what the intended use is.

As with all new technologies, there’s always something that is inevitably created that was never imagined by the original designers. What these new applications are is at this point just speculation. Now that anyone can buy one of these neat new chips, it’s going to be interesting to see what can be made with these parts.

Embed With Elliot: We Don’t Need No Stinkin’ RTCs

July 1, 2015 by Elliot Williams 68 Comments

A lot of microcontroller projects out there need some sense of wall-clock time. Whether you’re making (yet another) crazy clock, logging data, or just counting down the time left for your tea to steep, having access to human time is key.

The simplest solution is to grab a real-time-clock (RTC) IC or module. And there’s good reason to do so, because keeping accurate time over long periods is very hard. One second per day is 1/86,400 or around eleven and a half parts per million (ppm), and it’s tricky to beat twenty ppm without serious engineering.

Good RTC ICs like Maxim’s DS3231, used in the Chronodot, can do that. They use temperature correction logic and a crystal oscillator to get as accurate as five parts per million, or under half a second per day. They even have internal calendar functions, taking care of leap years and the day of the week and so on. The downside is the cost: temperature-compensated RTCs cost around $10 in single quantity, which can break the budget for some simple hacks or installations where multiple modules are needed. But there is a very suitable alternative.

What we’re looking for is a middle way: a wall-time solution for a microcontroller project that won’t break the bank (free would be ideal) but that performs pretty well over long periods of time under mellow environmental conditions. The kind of thing you’d use for a clock in your office. We’ll first look at the “obvious” contender, a plain-crystal oscillator solution, and then move on to something experimental and touchy, but free and essentially perfectly accurate over the long term: using power-line frequency as a standard.

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Retrotechtacular: Building Hammond Organ Tones

June 30, 2015 by Kristina Panos 19 Comments

Here’s a short film made by the Hammond Organ Company with the intent to educate and persuade potential consumers. Right away we are assured that Hammond organs are the cream of the crop for two simple reasons: the tone generator that gives them that unique Hammond sound, and the great care taken at every step of their construction.

Hammond organs have ninety-one individual electromagnetic tone wheel assemblies. Each of these generate a specific frequency based on the waviness of a spinning disk’s edge and the speed at which it is rotated in front of an electromagnet. By using the drawbars to stack up harmonics, an organist can build lush walls of sound.

No cost is spared in Hammond’s tireless pursuit of excellence. All transformers are wound in-house and then sealed in wax to make them impervious to moisture. Each tone wheel is cut to exacting tolerances, cross-checked, and verified by an audio specialist. The assembly and fine tuning of the tone generators is so carefully performed that Hammond alleges they’ll never need tuning again.

This level of attention isn’t limited to the guts of the instrument. No, the cabinetry department is just as meticulous. Only the highest-quality lumber is carefully dried, cut, sanded, and lacquered by hand, then rubbed to a high shine. Before it leaves the shop, every Hammond organ is subject to rigorous inspection and a performance test in a soundproofed room.

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