Astro Cat: Raspberry Pi Telescope Controller

December 5, 2017 by Tom Nardi 8 Comments

When somebody tackles an engineering problem, there are two possible paths: they can throw together a quick and dirty fix that fits their needs (the classic “hack”, as it were), or they can go the extra mile to develop a well documented solution that helps the community as a whole. We cover it all here at Hackaday, but we’ve certainly got a soft spot for the latter approach, even if some may feel it falls into the dreaded territory of “Not A Hack”.

When [Gary Preston] wanted to control his telescope and astrophotography hardware, he took the second path in a big way. Over the course of several posts on his blog, [Gary] walks us though the creation of his open source Raspberry Pi add-on board that controls a laundry list of sensors and optical gear. Just don’t call it a HAT, while it may look the part, [Gary] is very specific that it does not officially meet the HAT specifications put out by the Raspberry Pi Foundation.

Even if you aren’t terribly interested in peering into the infinite void above, the extremely detailed write-up [Gary] has done contains tons of multidisciplinary information that you may find useful. From showing how to modify the Pi’s boot configuration to enable true hardware UART (by default, the Pi 3 ties it up with Bluetooth) and level shifting it with a ST3232 to a breakdown of the mistakes he made in his PCB layout, there’s plenty to learn.

Astro CAT is a completely open source project, with the hardware side released under the CERN Open Hardware License v1.2, and the INDI driver component is available under the GPL v3.

If this looks a bit daunting for your first stab at astrophotography with the Raspberry Pi, fear not. We’ve covered builds which can get you up and running no matter what your budget or experience level is.

Slinky Walks Down Stairs And Picks Up 80m Band

December 4, 2017 by Tom Nardi 33 Comments

Originally intended as a way to stabilize sensitive instruments on ships during World War II, the Slinky is quite simply a helical spring with an unusually good sales pitch. But as millions of children have found out since the 1940’s, once you roll your Slinky down the stairs a few times, you’ve basically hit the wall in terms of entertainment value. So what if we told you there was yet another use for this classic toy that was also fun for a girl and a boy?

As it turns out, a cheap expandable metal coil just so happens to make for a pretty good antenna if you hook it up right. [Blake Hughes] recently took on this project and provided some detailed pictures and information for anyone else looking to hook a couple of Slinkies to their radio. [Blake] reports excellent results when paired to his RTL-SDR setup, but of course this will work with whatever kind of gear you might be using at these frequencies.

Before anyone gets out the pitchforks, admittedly this isn’t exactly a new idea. There are a few other write-ups online about people using a Slinky as a cheap antenna, such as this detailed analysis from a few years ago by [Frank Dörenberg]. There’s even rumors that soldiers used a Slinky from back home as a makeshift antenna during the Vietnam War. So this is something of an old school ham trick revived for the new generation of SDR enthusiasts.

Anyway, the setup is pretty simple. You simply solder the RF jack of your choice to two stretched out Slinkies: one to the center of the jack and one to outside. Then run a rope through them and stretch them out in opposite directions. The rope is required because the Slinky isn’t going to be strong enough when expanded to keep from laying on the ground.

One thing to keep in mind with a Slinky antenna is that these things are not exactly rated for outside use. Without some kind of treatment (like a spray on acrylic lacquer) , they’ll quickly corrode and fail. Though a better idea might simply to be to think of this as a temporary antenna that you put away when you’re done with. Thanks to the fact that the Slinky doesn’t get deformed even when stretching it out to maximum length, that’s relatively easy to accomplish.

If you’re looking for a good RTL-SDR to go along with your new Slinky antenna, check out this roundup of some of the options that are on the market as of 2017. You’ll probably need an upconverter to get down to the 80m band, so you might as well build that while you’re at it.

The German Space Program That Never Was

December 4, 2017 by Tom Nardi 89 Comments

A previous post discussed the creation of the V-2 rocket, the first man-made object to reach space. Designed and built at the Peenemünde Army Research Center during World War II, the V-2 was intended to be a weapon of mass destruction, but ended up being far more effective as a tool of discovery than it ever did on the battlefield. In fact, historians now estimate that more people died during the development and construction of the V-2 than did in the actual attacks carried out with it. But even though it failed to win the war for Germany, it still managed to change the world in another way: as it served as the basic blueprint for all subsequent rockets right up to modern-day vehicles.

But the V-2 wasn’t the only rocket-powered vehicle that the Germans were working on, a whole series of follow-up vehicles were in the design phase when the Allies took Berlin in 1945. Some were weapons, but not all. Pioneers like Walter Dornberger and Wernher von Braun saw that rocketry had more to offer mankind than a new way to deliver warheads to the enemy, and the team at Peenemünde had begun laying the groundwork for a series of rockets that could have put mankind into space years before the Soviets.

Continue reading “The German Space Program That Never Was” →

Tis The Season For Terror With DIY Krampus

November 30, 2017 by Tom Nardi 19 Comments

The holiday season is full of many sounds; walking through your neighborhood on a winter night you may hear time-honored songs, the tinkling of glasses, and the laughter of good company. But if the chilly wind also brings to your ear the panicked sounds of screaming children, you may have wandered a bit to close to [Tyler Garner]’s house.

Rather than old Saint Nick or a couple of reindeer, [Tyler] decided to top the roof of his home with a disturbingly well done rendition of everyone’s favorite��Austro-Bavarian goat-demon, Krampus. While he did finish the build off with a store-bought Krampus mask, every other component was made with about a 60/40 ratio of hardware to craft store scores. While your holiday decorations this year may not include any spawns of hell, the general construction techniques and resourcefulness [Tyler] shows in this build may come in handy when Halloween rolls around again.

The “skeleton” of Krampus is made up of PVC pipes and fittings mounted on an MDF base. Not only do the PVC fittings make it easy to recreate the rough anatomy of a humanoid figure, but if you don’t glue them all together, you can take it apart later for storage. We might have gone with something a little heartier than MDF for the base, but at least [Tyler] added a few pieces of galvanized pipe at the bottom to give it a little weight down low.

Things start to get interesting when [Tyler] adds sections of drainage pipe to his PVC skeleton to give it a more girth, as he was finding the bare PVC didn’t have a realistic presence when the robes were thrown over them. [Tyler] also uses expanding spray foam to soften up areas such as the hunched back, which may look messy but has the dual advantages of being cheap and fast.

The figure’s robes are made up of a patchwork of burlap, waterproofed with a spray on liner intended for pickup truck beds. With the application of red and black spray paint and the customary white fringe, it really nails the look.

A particularly nice detail is the hoof peeking out from beneath the robes, which [Tyler] made out of painted air-dry clay. It’s an awesome detail, though almost impossible to see once Krampus is mounted on the roof. Maybe it’s just us, but we think putting so much effort into a nearly hidden feature of a project is the true mark of a master craftsman; this is a secret little hoof that [Bob Ross] himself would be proud of.

While we can’t say we’ve played host to holiday scamps like Krampus or Belsnickle before, Hackaday has certainly seen its fair share of festive hacks over the years.

Refinishing A Vintage KitchenAid Mixer

November 30, 2017 by Tom Nardi 49 Comments

If you know anyone who is serious about baking, there’s a good chance you’ve seen one of these classic KitchenAid mixers. Built to last, they are often handed down generation to generation (or at least, when a newer model comes out), which is how [Kaitlin Flannery] received hers. While it didn’t look too bad considering its long life and the fact it’s been through a motor replacement already, she decided to spruce it up a bit by stripping it down and repainting the whole machine.

These KitchenAid mixers are solidly built and look highly serviceable, it’s refreshing to see a teardown that doesn’t involve any finicky plastic clips or glue. A standard philips screwdriver gets you inside the case, and a couple more screws allow the trim pieces to be removed.

Most of the work [Kaitlin] does is not completely unlike what you might have to do if you wanted to respray the fender of your car. You take off as much extra hardware as your patience allows, put painters tape over everything you want to keep over-spray off of, and then go to town.

To get the smooth metallic finish that you’d expect on a kitchen appliance, [Kaitlin] sands with 220 paper between the coats of hardware store Rust-Oleum. Generally we’d advise switching over to wet sanding at a higher grit once a few coats of paint have been laid down, but we can’t argue with the final results [Kailtin] got. The last coat is followed up with a clear enamel, which will help protect the finish from scratches; very important for a kitchen appliance.

[Kaitlin] does mention that she mistakenly taped off a bit more than she should have, and there’s still some of the original color visible on the rear of the machine. But beyond that, the finish looks fantastic, and with the new motor installed it looks like this machine is going to stick around long enough to get handed down a second time at least.

Hackaday has regrettably made few inroads into the kitchen as of late, one might get the impression that there isn’t a whole lot of overlap between the workbench and the counter-top. If you’ve got something you’ve made or remade sitting in your kitchen as you read this, by all means let us know.

Peer Review In The Age Of Viral Video

November 29, 2017 by Tom Nardi 73 Comments

Recently, a YouTube video has been making the rounds online which shows a rather astounding comparison between two printed models of the US Capitol. Starting with the line “3-D PRINTERS CAN NOW PRINT TWICE AS FAST”, the video shows that one print took four hours to complete, and the other finished in just two hours by virtue of vibration reducing algorithms developed at the University of Michigan. The excitement around this video is understandable; one of the biggest limitations of current 3D printer technology is how long it takes to produce a model of acceptable quality, and if improvements to the software that drives these machines could cut total print time in half, the ramifications would be immense.

In only a few weeks the video racked up tens of thousands of views, and glowing articles popped up with headlines such as: “How to cut 3D print times in half by the University of Michigan” and “University of Michigan professor doubles 3D printing speeds using vibration-mitigating algorithm“. Predictably, our tips line lit up with 3D printer owners who wanted to hear more about the incredible research that promised to double their print speed with nothing more than a firmware update.

The only problem is, the video shows nothing of the sort. What’s more, when pushed for details, the creators of the video are now claiming the same thing.

Continue reading “Peer Review In The Age Of Viral Video” →

Racing Simulator Built From Scrapheap Finds

November 24, 2017 by Tom Nardi 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.