Retrotechtacular: Stateside Assembly And Launch Of V-2 Rockets

April 21, 2015 by Kristina Panos 28 Comments

At the end of World War II, the United States engaged in Operation Paperclip to round up German V-2 rockets and their engineers. The destination for these rockets? White Sands Proving Grounds in the New Mexico desert, where they would be launched 100 miles above the Earth for the purpose of high altitude research.

This 1947 War Department Film Bulletin takes a look inside the activities at White Sands. Here, V-2 rockets are assembled from 98% German-made parts constructed before V-E day. The hull of each rocket is lined with glass wool insulation by men without masks. The alcohol and liquid oxygen tanks are connected together, and skins are fitted around them to keep fuel from leaking out. Once the hull is in place around the fuel tanks, the ends are packed with more glass wool. Now the rocket is ready for its propulsion unit.

In the course of operation, alcohol and liquid oxygen are pumped through a series of eighteen jets to the combustion chamber. The centrifugal fuel pump is powered by steam, which is generated separately by the reaction between hydrogen peroxide and sodium permanganate.

A series of antennas are affixed to the rocket’s fins. Instead of explosives, the warhead is packed with instruments to report on high altitude conditions. Prior to launch, the rocket’s tare weight is roughly five tons. It will be filled with nine tons of fuel once it is erected and unclamped.

At the launch site, a gantry crane is used to add the alcohol, the liquid oxygen, and the steam turbine fuels after the controls are wired up. The launch crew assembles in a blockhouse with a 27-foot-thick roof of reinforced concrete and runs through the protocol. Once the rocket has returned to Earth, they track down the pieces using radar, scouting planes, and jeeps to recover the instruments.

Thanks for the tip, [Thomas].

Retrotechtacular is a weekly column featuring hacks, technology, and kitsch from ages of yore. Help keep it fresh by sending in your ideas for future installments.

Snow Blower Turned Power Wagon

April 21, 2015 by Rich Bremer 32 Comments

Winter is now gone and it’s time to put away that snowblower. Well, it seems that [SWNH] either didn’t hear the news or thought not using his snowblower for most of the year was a waste of a great resource. No, he’s not using it to blow dirt around, he converted it into a Power Wagon.

A Power Wagon is just what it sounds like, a wagon that is motorized and it is used for moving stuff around your yard. [SWNH] started by disassembling the 2 stages of the snowblower. They came off as a unit with only 6 bolts. Next up, the wagon bed was made, starting with an angle iron frame with a plywood bottom and sides. Two large casters with rubber wheels supports the front of the wagon.

Using the power wagon is easy, fill up the bin and use the snowblower controls to drive the cargo around. [SWNH] says that it steers like a shopping cart. And since the wagon bed is bolt-on, it can be removed and the blower assembly re-installed next winter to take care of that pesky snow.

Powerwheels Racing Series In Detroit

April 20, 2015 by James Hobson 13 Comments

[Transistor-Man] and the gang finally got around to documenting their experience at the Detroit Makerfaire 2014 and the Powerwheels racing series. They weren’t planning on entering, but in a last-minute decision they decided to see if they could whip up an entry just over one week before the competition! They did — and it’s awesome. They call it the Chibi-Atomic-Jeep.

As the competition name implies, they had to base the vehicle off of a Powerwheels frame. Bunch of steel tubing, some TIG welding and a nice paint job, and they had the base frame of their vehicle. At the heart of it? An alternator from a van — surprisingly powerful and easy to control. They used cheap 8″ wheels from Harbor Freight Tools — they worked great, just didn’t last very long… By the time the races were over, they went through NINE of these tires. Good thing they’re cheap!

The most impressive part of the build is the gears. They made them using a water-jet cutter at the local hobby shop and a Bridgeport mill with an indexing head — not an easy task to complete!

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Interactive Software To Solve Crosstalk Problems

April 20, 2015 by Bil Herd 4 Comments

A link to this video demonstrating PCB cross-talk ended up in my mailbox the other day as I tend to stay on the mailing lists of the some of the high end CAD companies. There are some really interesting and powerful “mega-tools” that do things like plot noise density for decoupling analysis and extremely high speed timing analysis, though the costs of these tools are commensurate with their capabilities. This one is part of the Mentor Graphics PCB Simulation software.

The tool shown does the math needed to predict the induced voltage noise (cross-talk) generated by the proximity of noise sources to the noise susceptible elements, and the tool does so interactively. This is remarkable… in the past we would calculate some examples of trace width, spacing, and the type of signals involved, and then generate some rules of thumb that we tried to apply during the layout process. It was an educated guess that was sometimes not as close as we would have liked.

Virtual Scope Showing Predicted Crosstalk — Virtual Scope Showing Predicted Cross-talk

The cool part of this software is the interactive nature. One can learn the effects of placement on cross-talk in real time, which helps build an intuitive understanding.

I will add the standard disclaimer that a tool is exactly that, a tool, and it only represents an approximation of real life at best. It’s tempting to design to the tool itself, and many engineers have learned the limitation of a tool the hard way. Instead think of the tool as another opinion, or as mentioned, a learning aid to gather an intuitive feel for the effects of placement on circuit performance.

Driving A Brushless DC Motor Sloooooooowly

April 20, 2015 by Will Sweatman 68 Comments

Driving a brushless DC (gimbal) motor can be a pain in the transistors. [Ignas] has written up a nice article not only explaining how to do just this with an Arduino, but also explaining a little bit on how the process works. He uses a L6234 Three Phase Motor Driver, but points out that there are other ways to interface the BLDC motor with the Arduino.

A warning is warranted – this is not for the faint of heart. You can easily destroy your microcontroller if you’re not careful. [Ignas] added several current limiting resistors and capacitors as advised in the application note (PDF warning) to keep things safe.

Everything worked well at high speeds, but for slower speeds the motor was choppy. [Ingus] solved this riddle by changing over to a sine wave to drive the motor. Instead of making the Arduino calculate the wave, he used a look up table.

Be sure to check out his blog for full source and schematics. There is also a video demonstrating just how slow he can make the motor move below.

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VCF East X: The World’s Largest USB Thumb Drive

April 20, 2015 by Brian Benchoff 27 Comments

The Vintage Computer Festival last weekend featured racks and racks of old minicomputers, enough terminals for an entire lab, and enough ancient storage devices to save a YouTube video. These storage devices – hard disks, tape readers, and 8″ disk drives – were only connected to vintage hardware, with one exception: a DEC RL02 drive connected to a modern laptop via USB.

The DEC RL02 drive is the closest you’re going to get to a modern mechanical hard drive with these old machines. It’s a huge rack unit with removable platters that can hold 10 Megabytes of storage. [Chris] found one of these old drives and because he wanted to get into FPGA development, decided to create a USB adapter for this huge, old drive.

The hardware isn’t too terribly complex, with a microcontroller and an FPGA that exposes the contents of the drive over USB mass storage. For anyone trying to bootstrap a PDP-11 or -8 system, [Chris] could download disk images from the Internet, write them to the disk, and load up the contents of the drive from the minicomputer. Now, he’s using it with SimH to have a physical drive for an emulated system, but the controller really doesn’t care about what format the disk pack is in. If [Chris] formatted a disk pack with a FAT file system, he would have the world’s largest and heaviest USB thumb drive in the world.

Video below.

Update: As promised, [Chris] put all the code in a git

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Hackaday Los Angeles Event: Develop Your Hacking Superpowers

April 20, 2015 by Mike Szczys 4 Comments

When we get together we like to build stuff, and that’s what has been motivating us as we work toward Hackaday Prize Worldwide: Pasadena. This two-day event held May 9th and 10th in the Los Angeles area is not to be missed. We are presenting a workshop, speakers, hacking, and socializing. Drop what you’re doing and get a ticket for the low-low price of being an awesome person.

On Saturday the ninth, Hackaday opens our doors for the workshop: “Zero to Product”. [Matt Berggren] leads the workshop. He is well known for running the Hardware Developer’s Didactic Galactic up in San Francisco (a meetup that we love to attend). [Matt] comes from a hardware design background and has done it all. He’s been involved in building schematic and PCB tools, been run through the startup gauntlet, and has a ton of hardware experience including everything from FPGA layout to getting that product out the door.

The workshop covers the things you need to consider when producing production-quality, professional-level circuit boards. Don’t be afraid of this, the discussion is approachable for the newcomer as well as the experienced hacker. Of course a PCB does not a product make so the conversation will also move through component selection, enclosures, best practices, and much more.

You Can’t Miss these Talks

[Elecia White]

[Elecia] is an embedded systems expert and a Hackaday Prize judge in both 2014 and 2015. Elecia will be demonstrating a gadget designed to familiarize engineers with the capabilities of inertial various sensors like accelerometers, gyroscopes, and magnetometers.

[Samy Kamkar]

[Samy] is a privacy and security researcher, has had a number of projects featured on Hackaday. The most notable in our minds is the wireless keyboard sniffer he built into a cellphone charger. He’ll be discussing that build as well as some other projects like his drone army.

We do have a few other speakers and lighting talks lined up but we don’t want to announce until we have final confirmation from those presenters. Please check on the event page for updates.

Show Off Your Hacks and Build More On-Site

We have the space, we have the people, add some food and beverage and now you’re talking. On Saturday evening we’ll warp up the talks and workshops, throw on some tunes, and pull out the projects we’ve been working in our spare time.

This casual hang-out is a great time to find answers and advice for that one problem that’s been tripping you up. We’ll make sure there’s something to fill your belly and keep you happy while you think about what you want to hack on the following day.

Sunday is Open Hack Day. Want to work on the concepts you picked up from Saturday’s workshop? Great, we can help with that! We’ll also have hardware development boards on-hand from our Hackaday Prize Sponsors, other random hackable stuff, and of course you may bring your own equipment and get down to business. Anything is fair game but we’re especially excited to see what people are building as their 2015 Hackaday Prize entries!

In case you missed the ticket link, please RSVP now. We’ll see you in May!