Retrotechtacular: How To Repair A Steam Locomotive

November 24, 2017 by 41 Comments

Steam locomotives, as a technological product of the 19th century, are not what you would imagine as fragile machines. The engineering involved is not inconsequential, there is little about them that is in any way flimsy. They need to be made in this way, because the huge energy transfer required to move a typical train would destroy lesser construction. It would however be foolish to imagine a locomotive as indestructible, placing that kind of constant strain on even the heaviest of engineering is likely to cause wear, or component failure.

A typical railway company in the steam age would therefore maintain a repair facility in which locomotives would be overhauled on a regular basis, and we are lucky enough to have a 1930s film of one for you today courtesy of the British London Midland and Scottish railway. In it we follow one locomotive from first inspection through complete dismantling, lifting of the frame from the wheels, detaching of the boiler, inspection of parts, replacement, and repair, to final reassembly.

We see steps in detail such as the set-up of a steam engine’s valve gear, and it is impressed upon us how much the factory runs on a tight time schedule. Each activity fits within its own time window, and like a modern car factory all the parts are brought to the locomotive at their allotted times. When the completed locomotive is ready to leave the factory it is taken to the paint shop to emerge almost as a new machine, ready for what seems like a short service life for a locomotive, a mere 130 thousand miles.

The video, which we’ve placed below the break, is a fascinating glimpse into the world of a steam locomotive servicing facility. Most Hackaday readers will never strip down a locomotive, but that does not stop many of them from having some interest in the process. Indeed, keen viewers may wish to compare this film with “A Study in Steel“, another film from the LMS railway showing the construction of a locomotive.

LMS Jubilee class number 5605, “Cyprus”, the featured locomotive in this film, was built in 1935, and eventually scrapped in 1964 as part of the phasing out of steam traction on British railways.

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A Giant Magellan Telescope Needs Giant Mirrors

November 24, 2017 by 47 Comments

The Giant Magellan Telescope doesn’t seem so giant in the renderings, until you see how the mirrors are made.

The telescope will require seven total mirrors each 27 feet (8.4 meters) in diameter for a total combined diameter of 24.5 meters. Half of an Olympic size pool’s length. A little over four times the diameter of the James Webb Space Telescope.

According to the website, the mirrors are cast at the University of Arizona mirror lab and take four years each to make. They’re made from blocks of Japanese glass laid out in a giant oven. The whole process of casting the glass takes a year, from laying it out to the months of cooling, it’s a painstaking process.

Once the cooling is done there’s another three years of polishing to get the mirror just right. If you’ve ever had to set up a metal block for precision machining on a mill, you might have an idea of why this takes so long. Especially if you make that block a few tons of glass and the surface has to be ground to micron tolerances. A lot of clever engineering went into this, including, no joke, a custom grinding tool full of silly putty. Though, at its core it’s not much different from smaller lens making processes.

The telescope is expected to be finished in 2024, for more information on the mirror process there’s a nice article here.

Racing Simulator Built From Scrapheap Finds

November 24, 2017 by 13 Comments

Paradise means something different for everyone, it could be a sitting by a fire on a rainy night or lying on a sun-kissed beach. But for us, and makers like [liltreat4you], it’s a well stocked scrap pile out behind the house. After buying a racing wheel and pedals for his Xbox, he took a trip out to his little slice of paradise and found nearly all the hardware he needed to build a professional looking race simulator. According to his breakdown, most of the money he spent on this build ended up going into that sweet red paint job and the speed-enhancing stickers.

Everything the light touches is our kingdom.

Not all of us are as lucky as [liltreat4you], and we probably won’t just happen upon a driver’s seat out of a Mazda, or a bunch of perfectly bent metal pipes from an old trampoline out on the back forty. But trolling Craigslist or cruising around for flea markets can still get you parts like these for cheap, so try not to be too discouraged if your backyard isn’t quite as well stocked.

Once he had the metal pipes and seat from the car, the rest of the build came together pretty quickly. After building an oval out of his salvaged pipes, he attached the seat and the arms that would eventually hold the steering wheel and display. A plate was also added at the bottom for the pedals to sit on. By using long bolts, [liltreat4you] was even able to add a degree of adjustment to the wheel position. Being that he got his seat out of a real car, there’s the usual adjustment you’d expect there as well.

Speaking of which, [liltreat4you] casually mentions that you should disconnect the battery of the donor vehicle before taking out the seat, as it’s possible that the removal of the seat or the disconnection of the seat harness can cause the airbags to deploy. We can neither confirm nor deny this, but it’s probably safe advice to follow.

The purists out there may claim that what [liltreat4you] has put together doesn’t quite meet the definition of simulator in its current form. But with the addition of some instrumentation and just a bit of physical feedback, he’ll be well on his way to the complete driving experience.

Precision Voltage Reference Source

November 23, 2017 by 10 Comments

[barbouri] found a few old (vintage?) parts from the early ’80’s while rummaging through his parts bin, and quickly spun out a small PCB to build a 10.000 V reference using these old ICs. Throwing together a small number of parts, he was able to build a source which might be good enough to use as a reference for another circuit or provide a quick calibration check for some of his bench instruments that have a resolution of 1 mV or maybe even 100 μV.

The AD584* pin programmable precision voltage references have been available since the ’80’s and offer four programmable output voltages of 10.000 V, 7.500 V, 5.000 V, and 2.500 V. The chip is laser-trimmed to ensure high accuracy and low temperature coefficient and requires just a few external components to function. It is available in TO-99 hermetically sealed metal can and 8-pin DIP variants. The “S” version of the device that [barbouri] used provides a temperature coefficient of 30 ppm/°C max over a -55 °C to +125 °C temperature range but other versions of the chip offer a better stability. Analog Devices seem to have discontinued the “L” version (pdf), since it is no longer listed in the current data sheet, but you can still get them from a few sources. The “L” version has a temperature coefficient of just 5 ppm/°C.

Using quality parts such as high stability resistors and TO-99 PTFE socket with gold-plated contacts, his observations confirm that the unit is stable within 30 μV, with a very slow voltage increase of a few microvolts every 6 hours. A 15 V linear regulator powers the device with input power coming from an external wall wart. A small aluminum enclosure houses the device, with two gold-plated 4 mm sockets for the output. If you would like to build your own, his board design is hosted on OSH park, or you can download the Eagle CAD design files. He’s posted all links on his blog post, and provides part numbers for all of the parts used. [barbouri] has been doing a good job of building handy devices for his work bench – check out his well-built milli Ohm Meter that we had featured earlier.

Bringing MATLAB To A Vacuum Near You

November 23, 2017 by 7 Comments

The essence of hacking is modifying something to do a different function. Many of us learned as kids, though, that turning the family TV into an oscilloscope often got you into trouble.

These days, TVs are flat and don’t have high voltage inside, but there’s always the family robot, often known as a Roomba. Besides providing feline transportation, these little pancake-shaped robots also clean floors.

If you don’t want to evict the cat and still get a robust domestic robot platform for experimentation, about $200 will get you a Roomba made to be hacked — the iRobot Create 2. [Gstatum] has a tutorial for using a Raspberry Pi and MATLAB to get one quickly running and even doing basic object recognition using the Pi’s camera.

The code even interfaces with Twitter. The impressive part is the code fits on about a page. This isn’t, however, completely autonomous. It uses a connected phone’s sensor’s so that the phone’s orientation controls the robot’s motion, but the robot does use sensors to prevent driving into walls or falling off a cliff. It also can detect being picked up and uses the Pi’s camera to detect a green flag.

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Dumb Box? Make It Really Smart!

November 23, 2017 by 6 Comments

[Stephen Harrison]’s Really Smart Box is a great concept, it’s simultaneously a simple idea while at the same time being super clever. The Really Smart Box isn’t really a box; it’s a drop-in platform that can be made any size, intended to turn any dumb storage box into one that helps manage and track levels and usage of any sort of stock or consumable.

It does this by measuring the weight of the stuff piled on top of it, while also monitoring temperature and humidity. The platform communicates this information wirelessly to a back end, allowing decisions to be made about stock levels, usage, and monitoring of storage conditions. It’s clearly best applied to consumables or other stock that comes and goes. The Really Smart Box platform is battery-powered, but spends most of its time asleep to maximize battery life. The prototype uses the SigFox IoT framework for the wireless data, which we have seen before in a wireless swimming pool monitor.

This is still just a prototype and there are bugs to iron out, but it works and [Stephen] intends to set-and-forget the prototype into the Cambridge Makespace with the task of storing and monitoring 3D printer filament. A brief demo video is embedded below.

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Swarm Of Servos Plays This Robotic Glockenspiel

November 23, 2017 by 7 Comments

It’s the happiest sounding instrument in the marching band, and it’s got the best name to boot. It’s the glockenspiel, and if this robotic glockenspiel has anything to say about it, the days of human glockenspielists are numbered.

In its present prototype form, [Averton Engineering]’s “Spielatron” looks a little like something from a carousel calliope or an animatronic pizza restaurant band. Using a cast-off glockenspiel from a school music room as a base, the Spielatron uses four mallets to play all the notes. Each key is struck by a mallet secured to a base made of two servos. For lack of more descriptive mallet terminology, these servos provide pan and tilt so the mallet can strike the proper keys. The video below shows the Spielatron’s first recital.

An Arduino runs the servos and a MIDI interface; unfortunately, this version can’t play chords and is a little limited on note length, but upgrades are on the way. We’ve seen a robotic glockenspiel before with a similar design that might have some ideas for increasing performance. But if you’re looking for a more sublime sound, check out this dry ice-powered wind chime.

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