Hackaday Links: May 25, 2014

May 25, 2014 by Mike Szczys 13 Comments

[Matt] wanted his own light saber. You could argue that this is nearly as dangerous since you can’t see the beam and it doesn’t end a few feet past the business end of the grip. Plus there’s that who “not actually a Jedi” thing.

We don’t know if retro computing fans are going to love or hate this (translated). On the one hand it’s pretty cool to see a ZX81 clone up and running. On the other hand, an Amiga 600 case was sacrificed to serve as the body for the hack. [Thanks Juan]

Watchdog timer. If you know what that is your mind immediately says “good idea” when you hear the word. If you don’t know, you need to learn. Watchdogs are reset timers that are built into most microcontrollers. If your firmware gets stuck and doesn’t maintain the timer’s counter at a regular interval the watchdog it will perform a hardware reset and hopefully your hardware will start functioning again. Here’s a guide for using the watchdog in an Arduino, but the concepts are pretty much universal.

We see all kinds of stepper-motor based music machines. One of our favorites was this recent floppy drive jukebox. But not every song is going to sound good on this type of hardware. One that does sound especially neat is the Doctor Who theme on an array of 8 drives.

And finally, if you’re struggling with surface mount soldering we recommend grabbing two soldering irons. But in a pinch just grab some heavy gauge copper wire and wrap it around your soldering iron tip. It ends up being a two-point soldering iron set for the size of specific components such as 0805 resistors. [Thanks Rupert]

Ask Hackaday: Can Battery-Free Bluetooth Item Locating Tags Exist?

May 21, 2014 by Mathieu Stephan 220 Comments

[Vishak] tipped us about the iFind Kickstarter campaign, a 1.25×1.06×0.09″ (32x27x2.4mm) tag meant to be attached to anything you may lose in your daily life. This device communicates with Bluetooth Low Energy (BLE) enabled smartphones, has a 200ft (60m) detection range and a loud alarm. What is interesting to mention is that this device doesn’t need any battery to operate as it

recycles electromagnetic energy and stores it in a unique power bank.

As you can guess, this particular claim intrigued the Hackaday team given that we never featured so small energy harvesting devices. The ‘closest’ thing that comes to our minds is the Allsee project, a simple gesture recognition device that uses existing wireless signals (TV and RFID transmissions) to extract any movement that occur in front of it. However the antenna was quite big and very little power was extracted.

A quick Google search let us know that Bluetooth Low Energy solutions usually consume an idle current of around 10uA @ ~3V. The (very) successful Sticknfind campaign which promoted the same battery-enabled product claimed a one year autonomy with a CR2016 battery and a 100ft range, leading to a ~90mAh/24/30.5/12 = 10.2uA idle current. As we’re not expert on the subject, we would like to ask our readers if they ever came across such energy harvesting performances (3V*10.2uA = 30uW) in a normal home environment. Our very bad maths indicate that if one would like to extract power from a typical Wifi router located 2 meters from you emitting 0.5Watts of power (in a perfect vacuum environment) with a 32*27mm = 864mm = 0.000864m² tag you’d only be able to get 0.5 * (0.000864/(4*pi*2*2)) = 8.6uW.

It is therefore too bad that we can’t see in the presentation video what is inside the iFind, nor more details about the patent pending technologies involved. We hope that our dear readers will enlighten us in the comments section below.

Retrotechtacular: Once Upon A Punched Card

May 20, 2014 by Brian Benchoff 27 Comments

card

Ah, the heady days of the early 60s, where companies gave their salesmen exquisitely produced documentaries, filled with incidental music written by the best composers of the era, and a voice actor that is so unabashedly ordinary you would swear you’ve heard him a hundred times before. It’s a lot better than any PowerPoint presentation anyone could come up, and lucky for us, these 16mm films are preserved on YouTube for everyone to enjoy. This one was sent out to IBM sales reps pushing a strange technology called a ‘punched card’, a system so efficient it will save your company tens of thousands of dollars in just a few short years.

Like most explanations of what a punched card does, this IBM documercial begins with the history of the Jacquard loom that used punched cards for storing patterns for textile weaving. In a rare bit of historical context befitting IBM, this film also covers the 1880 US census, an important part in the evolution of punched cards being used not as instructions for a loom, but data that could be tabulated and calculated.

The United States takes a census every ten years. The tenth census of 1880 took so long to compile into the data – seven years – it was feared the next census of 1890 wouldn’t be complete until the turn of the century. This problem was solved by [Herman Hollerith] and his system of encoding census data onto punched cards for tabulation. [Hollerith] would later go on to found the Tabulating Machine Company that would later merge with two other companies to form IBM. Isn’t it great that IBM chose to include that little nugget in their film.

As a point of interest, the film does contain a short pitch for IBM punched card writers, sorters, and calculators – the backbone of IBM’s medium to large size business sales. At the time this film was produced (1964) IBM was ready to announce the System/360, what would become the de facto mainframe for businesses of all sizes. Yes, the /360 also used punched cards, but we wonder how many angry phone calls the sales reps received months after showing this film.

Hackaday Links: May 18, 2014

May 18, 2014 by Brian Benchoff 9 Comments

Think the original Pong is cool? How about point to point Pong? [v8ltd] did it in three months, soldering all the leads directly to the chip pins. No sockets required. It’s insane, awesome, a masterpiece of craftsmanship, and surprising it works.

[Jeremy Cook] is building a servo-powered light graffiti thing and needed a laser diode. How do you control a laser pointer with a microcontroller? Here’s how. They’re finicky little buggers, but if you get the three-pack from Amazon like [Jeremy] did, you get three chances to get it right.

NFC tags in everything! [Becky] at Adafruit is putting them in everything. Inside 3D printed rings, glued onto rings, and something really clever: glued to your thumbnail with nail polish. Now you can unlock your phone with your thumb instead of your index finger.

Photographs capture still frames, but wouldn’t it be great if a camera could capture moving images? No, we’re not talking about video because this is the Internet where every possible emotion, reaction, and situation can be expressed with an animated GIF. Meet OTTO, the camera that captures animated GIFs! It’s powered by the Raspberry Pi compute module, so that’s interesting.

[Nate] was getting tired of end mills rolling around his bench. That’s a bad thing. He came up with a solution, though: Mill a piece of plywood into a tray to hold end mills.

The Da Vinci printer, a printer that only costs $500 because they’re banking on the Gillette model, has been cracked wide open by resetting the DRM, getting rid of the proprietary host software, and unbricking the device. Now there’s a concerted effort to develop custom firmware for the Da Vinci printer. It’s extraordinarily bare bones right now, but the pins on the microcontroller are mapped, and RepRap firmwares are extremely modular.

Fail Of The Week: Projector LED Retrofit

May 15, 2014 by Mike Szczys 30 Comments

fotw-projector-repair

That’s a deal for a project, how hard could it be to fix it up?

If you’re a real hacker we’d wager you’ve fallen for this type of thought process before. [Luft] bought this used Sharp XR-10X-L projector about a year back and planned to retrofit it with an LED bulb. He gathered all the parts and got to work, successfully testing and installing the modifications. But as luck would have it, the project is stuck in some type of boot loop.

This fail is certainly not for lack of preparation. The first post documenting his adventure shows that the hack has been done before, he acquired the service manual for this particular hardware, and he did his homework when ordering the parts. Success requires circumventing some sensors which ensure the case and internals are in place, and making sure the electronic status of the ballast is reported correctly event though it’s not needed for the LED source. Power-on gets as far as illuminating all the indicator lights in green as it should, but is then followed closely by a reboot sequence.

He tried watching the serial port to see if he can get any status info there but no dice. In keeping with the nature of this column, let’s see if we can provide any constructive troubleshooting advice in the comments.

Fail of the Week is a Hackaday column which runs every Wednesday. Help keep the fun rolling by writing about your past failures and sending us a link to the story — or sending in links to fail write ups you find in your Internet travels.

The Hacklet #3

May 14, 2014 by Eric Evenchick 2 Comments

The third issue of The Hacklet has been released. In this issue, we start off with a roundup on the Sci-Fi Contest which recently concluded. After seeing the many great hacks you came up with for that contest, we’re looking forward to seeing what you think of for The Hackaday Prize.

Next up, we take a look at two hacks that deal with switching mains, which is a feature that most home automation projects need. These high voltage switches can be dangerous to build, but one hack finds a safe and cheap way to do it. The next looks at building your own high voltage circuitry.

Finally, we talk about two laser hacks. The first is practical: a device for exposing resins and masks using a laser. The second is just a really big laser, built from hardware store parts. Who doesn’t like big lasers? We definitely like big lasers, and so does the FAA.

Retrotechtacular: Forging Of Chain By Smiths

May 13, 2014 by Brian Benchoff 36 Comments

Ah, the days when men were men and people died of asbestos related illnesses in their 30s. Let this video take you back to the ancient times when chains were forged by hand, destructively tested using wooden capstans, and sent off to furnish the ships of the line, way back in the year 1940.

The video is something of an advertisement for the Netherton iron works, located in the English midlands. Founded sometime in the mid 19th century, it appears the tooling and machinery didn’t change much the hundred years before this was filmed.

The chain begins as a gigantic mass of wrought iron bars brought in from a forge. These bars are stockpiled, then sent through chain shears that cut them into manageable lengths a foot or so long. The next scene would probably look the same in 1940 as 1840, with gangs of men taking one of the bars, heating it in a forge, beating it on an anvil, and threading it through the last link in the chain they worked on. This isn’t the satisfying machinations of industrial automata you’d see on How It’s Made. No, this is hard manual labor.

Whether through simple quality control or an edict from the crown, the completed chains are tested, or more specifically, proofed. Yard long samples are tested to their failure point, and entire chains are proofed to their carrying capacity in 15 fathom ( 90 feet) long lengths. These chains are then examined link by link, stamped and certified, and sent off to mines, factories, tramp steamers, and battleships.

Although the Netherton iron works no longer exists, it did boast a few claims to fame in its day. It manufactured the anchors and chain for both the Titanic and Lusitania. Of course, such a large-scale production of wrought chain in such an archaic method would be impossible today; today, every wrought iron foundry has been shuttered for decades. If you’ve ever wondered how such massive things were made with a minimal amount of machinery, though, there you go.

Continue reading “Retrotechtacular: Forging Of Chain By Smiths” →