Fun With Fire: Oxy-Acetylene Basics

November 14, 2016 by Dan Maloney 30 Comments

If generations of Hollywood heist films have taught us anything, it’s that knocking off a bank vault is pretty easy. It usually starts with a guy and a stethoscope, but that never works, so the bad guys break out the cutting torch and burn their way in. But knowing how to harness that raw power means you’ve got to learn the basics of oxy-acetylene, and [This Old Tony]’s new video will get your life of crime off on the right foot.

In another well-produced video, [Tony] goes into quite a bit of detail on the mysteries of oxygen and acetylene and how to handle them without blowing yourself up. He starts with a tour of the equipment, including an interesting look at the internals of an acetylene tank — turns out the gas is stored dissolved in acetone in a porous matrix inside the tank. Working up the hoses, he covers the all-important flashback arrestors, the different styles of torches, and even the stoichiometry of hydrocarbon combustion and how adjusting the oxygen flow results in different flame types for different jobs. He shows how oxy-acetylene welding can be the poor man’s TIG, and finally satisfies that destructive urge by slicing through a piece of 3/8″ steel in under six seconds.

We’ve always wanted a decent oxy-acetylene rig, and [Tony] has convinced us that this is yet another must-have for the shop. There’s just so much you can do with them, not least of which is unsticking corroded fasteners. But if a blue wrench is out of your price range and you still want to stick metal together, you’ll want to learn how to braze aluminum with a propane torch.

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PLC And Linear Actuators Automate Double-Hung Windows

November 13, 2016 by Dan Maloney 15 Comments

Very few residential architectural elements lend themselves to automation, with doors and windows being particularly thorny problems. You can buy powered doors and windows, true, but you’ll pay a pretty penny and have to go through an expensive remodeling project to install them. Solving this problem is why this double-hung window automation project caught our eye.

Another reason we took an interest in this project is that [deeewhite] chose to use a PLC to control his windows. We don’t see much love for industrial automation controllers around here, what with the space awash in cheap and easy to use microcontrollers. They have their place, though, and a project like this is a good application for a PLC. But the controller doesn’t matter at all if you can’t move the window, for which task [deeewhite] chose 12V linear actuators. The fact that the actuators are mounted in the center of the window is probably necessary given the tendency of sashes to rack in their frames and jam; unfortunately, this makes for a somewhat unsightly presentation. [deeewhite] also provides the ladder logic for his PLC and discusses how he interfaces his system with Alexa, a WeMo and IFTT.

We’d love to see this project carried forward a bit with actuators hidden under the window trim, or a rack and pinion system built into the window tracks themselves. This is a pretty good start and should inspire work on other styles of windows. While you’re at it, don’t forget to automate the window blinds.

[via r/DIY]

Raspberry Pi Spies On… Err… Monitors Baby

November 12, 2016 by Dan Maloney 7 Comments

“Quick! We’re having a baby and we need a baby monitor!” Rather than run to the local big box and plunk down cash for an off-the-shelf solution, any self-respecting hacker would rise to the challenge and hit the shop to build something like this live streaming eye-in-the-sky baby camera. Right?

At least that’s how [Antibore] handled the situation, and the results are pretty good. He designed his build around an old Raspberry Pi 2 that was hanging around. That required a WiFi adapter, and since he wanted video and audio he needed a camera and mic. The first USB mic had a nice compact design but didn’t perform well, so a gutted gooseneck mic soldered right to the USB connector joined the design spec. A camera module, cell-phone quick charge battery bank, and a 3D printed case round out the BOM. A knitted cozy to keep it looking warm and fuzzy was provided by the mother-to-be — although we think it looks a little like [Mike Wazowski].

This self-contained unit will work anywhere it has access to a WiFi network. Mounted on the baby carrier, it’ll provide a live stream to any browser and provide the new parents with a little peace of mind.

There are a lot of baby monitors on the market, some of them terrible and in need of a rebuild. Kudos to [Antibore] for deciding to roll his own custom solution and for getting it done before the blessed event. Now how about painting that nursery?

Better Tornado Warnings With Polygons And Pi

November 11, 2016 by Dan Maloney 16 Comments

Everyone pays close attention to the weather, but for those who live where tornadoes are prevalent, watching the sky can be a matter of life and death. When the difference between making it to a shelter or getting caught in the open can be a matter of seconds, it might make sense to build an internet enabled Raspberry Pi weather alert system.

We know what you’re thinking – why not just buy an off-the-shelf weather alert radio with Specific Area Message Encoding (SAME) reporting, or just rely on a smartphone app? As [Jim Scarborough] explains, living in the heart of Tornado Alley and having had a brush with tragedy as a kid teaches you not to be complacent with severe weather. He found a problem with the SAME system: lack of locational granularity below the county level, leading to a tendency to over-warn during tornado season. [Jim]’s build seeks to improve SAME by integrating National Weather Service polygon warnings, which define an area likely to see a severe weather event as a collection of geographic vertices rather than a political unit. He’s using a Raspberry Pi NOAA weather radio receiver with SAME decoding, and while details are sparse and the project is ongoing, the idea seems to be to use the Pi to scrape the NWS site for polygon data once a county-level warning is issued.

It’s an interesting idea, and one we’ll be keeping an eye on as [Jim] continues his build. In the meantime, you can brush up on weather radio and SAME encoding with this Arduino SAME decoder.

[via r/weather]

Really Big Digital Clock Finds Use For Really Big 3D Printer

November 10, 2016 by Dan Maloney 22 Comments

What does it take to make a really big digital clock? If [Ivan Miranda]’s creation is any gauge, it takes a really big 3D printer, an armful of Neopixel strips, and a ton of hot melt glue.

It looks like [Ivan]’s plus-size clock is mainly an exercise for his recently completed large-bed custom 3D printer, in itself a project worth checking out. But it’s a pretty ambitious project, and one that has some possibilities for enhancements. Each of the four seven-segment displays was printed separately, with a black background, translucent white for the segments, and recesses for five RGB LEDs each. The four digits and colon spacer are mated together into one display, and an ESP8266 fetches the time from a NIST server and drives the segments. What’s really interesting about [Ivan]’s projects is that he constrains himself to finishing them each in a week. That explains the copious amount of hot glue he uses, and leaves room for improvements. We’d love to see this display built into a nice walnut case with a giant red diffusing lens. Even as it stands it certainly makes a statement.

We’ve featured other outsized seven-segment displays before, but few as big as this one.

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Fail Of The Week: Upcycling Failed 3D Prints

November 8, 2016 by Dan Maloney 29 Comments

Is it possible to recycle failed 3D prints? As it turns out, it is — as long as your definition of “recycle” is somewhat flexible. After all, the world only needs so many coasters.

To be fair, [Devin]’s experiment is more about the upcycling side of the recycling equation, but it was certainly worth undertaking. 3D printing has hardly been reduced to practice, and anyone who spends any time printing knows that it’s easy to mess up. [Devin]’s process starts when the colorful contents of a bin full of failed prints are crushed with a hammer. Spread out onto a properly prepared (and never to be used again for cookies) baking sheet and cooked in the oven at low heat, the plastic chunks slowly melt into a thin, even sheet.

[Devin]’s goal was to cast them into a usable object, so he tried to make a bowl. He tried reheating discs of the material using an inverted metal bowl as a form but he found that the plastic didn’t soften evenly, resulting in Dali-esque bowls with thin spots and holes. He then flipped the bowl and tried to let the material sag into the form; that worked a little better but it still wasn’t the win he was looking for.

In the end, all [Devin] really ended up with is some objets d’art and a couple of leaky bowls. What else could he have done with the plastic? Would he have been better off vacuum forming the bowls or perhaps even pressure forming them? Or does the upcycling make no sense when you can theoretically make your own filament? Let us know in the comments how you would improve this process.

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Neopixels Light The Way In Pressure-Sensitive Floor

November 7, 2016 by Dan Maloney 8 Comments

It’s got a little “Saturday Night Fever” vibe to it, but this pressure-sensitive LED floor was made for gaming, not for dancing.

Either way, [creed_bratton_]’s build looks pretty good. The floor is a 5×6 grid of thick HDPE cutting boards raised up on a 2×4 lumber frame. Each cell has a Neopixel ring and a single force-sensitive resistor to detect pressure on the pad. Two 16-channel multiplexers were needed to consolidate the inputs for the Arduino that’s running the show, and a whole bunch of wall warts power everything. The video below shows a little of the build and a look under the tiles. It’s not clear exactly what game this floor is for, but you can easily imagine a maze or some other puzzle that needs to be solved with footsteps.

Light-up floors are nothing new here, what with this swimming pool dance floor. But this interactive dance floor comes close to the gaming aspect of [creed_bratton_]’s build.

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