For some of us, there are few sounds more satisfying than the deep resonant “thunk” of a high quality toggle switch slamming into position. There isn’t an overabundance of visceral experiences when working with electronics, so we like to savor them when we get the chance. But of course there’s no accounting for taste, and we suppose there are even situations where a heavy physical switch might not be the best solution. So what do you do?
Enter the latching power circuit, often referred to as a “soft” switch. [Chris Chimienti] has recently put together a fascinating video which walks the viewer through five different circuits which can be used to add one of these so-called soft power switches to your project. Each circuit is explained, diagramed, annotated, and eventually even demonstrated on a physical breadboard. The only thing you’ve got to do is pick which one you like the most.
There’s actually a number of very good reasons to abandon the classic toggle switch for one of these circuits. But the biggest one, somewhat counterintuitively, is cost. Even “cheap” toggle switches are likely to be one of the most expensive components in your bill of materials, especially at low volume. By comparison, the couple of transistors and a handful of passive components it will take to build out one of these latching circuits will only cost you a couple of cents.
Even if you aren’t in the market for a new way to turn off your projects, this roundup of circuits is a fantastic reminder of how powerful discrete components can be. In an age where most projects seem assembled from pre-fabbed modules, it’s occasionally refreshing to get back to basics.
Continue reading “Ditch The Switch: A Soft Latching Circuit Roundup”
There’s something special about improvised weapons built for the upcoming zombie apocalypse. Whether it’s a Lousiville Decapitron or a shotgun revolver, we’re always fascinated by homemade weapons. Here’s a few that rolled into the tip line over the last few weeks:
You call that a knife?
[Joerg Sprave], a.k.a. that German guy on YouTube that has fun with slingshots, built a spinning steak knife saw thing. Basically, it’s eight steak knives attached to a wheel and driven with an electric drill. It’s not a terribly complex build, but it does give off a zombie apocalypse/first person shooter melee weapon vibe.
Battery cannon, because why not
Why use potatoes when you can use D-cell batteries? [CasterTown] on YouTube put together a small propane-powered spud gun that can put a battery through a car door. This isn’t the first time we’ve seen batteries used as ammo, but it’s still an extremely powerful build.
Oh man the 60s were cool.
Back in the 60s, safety wasn’t a huge concern. Any 10-year-old could walk into a dime store and buy Jarts – a game consisting of kids throwing sharp spikes at each other. Also, magazines had descriptions of how to build a freaking mortar in a backyard. Able to make a 20-foot grouping at 1900 feet, this would probably merit a visit from a SWAT team today. Needless to say, don’t try this at home.
Don’t do this. Please.
Last but not least is [Rocketlab] and [SadisticTheory]’s $15 flamethrower. It’s just a gas tank from a 2-stroke engine, a 12 volt battery and a pump. Common sense requires us to mention this build is very,
very illegal (apparently it is legal)and extremely unsafe. Don’t replicate this build.
Actually, we take that back. You shouldn’t build any of these weapons because they’re very dangerous. Just think of these as a neat thing to look at. Let other people hurt themselves. You may complain about how unsafe these weapons are in the comments.
When the idea of an engine hacks theme was being kicked around at Hack a Day, the subject of rocket engines was one of the first to come up. There was a problem though; solid rocket motors are far too common to be interesting, and even hybrid rocket engines are becoming passé. We’ve never seen a liquid-fuel rocket build before, so that’s what this roundup evolved into.
First up is [Robert Watzlavick], who has been has been building liquid fueled engines for the last decade. He started out with an uncooled kerosene/LOX whose death is seen in the title pic for this post. Lately he’s been working on a monster of an engine that is projected to deliver over 1,000 Newtons of thrust. As with many of the early rockets that launched man into space, [Robert] uses kerosene and liquid oxygen for fuel. This man knows his stuff.
Next up is a ‘kit’ liquid fuel rocket, the SS67B-3, that’s based on the German WWII Taifun missile. This engine is about as basic as you can get. There’s one fuel tank that holds both the Hydrogen Peroxide oxidizer and gasoline fuel. Both are blasted into the combustion chamber with pressurized gas. we found a write-up on this kit with some good pictures, but no video.
If high pressures, glowing metal, and huge flames pique your interest, there’s also a fabulous e-book (PDF warning) available that is a reprint of How to Design, Build and Test Small Liquid-Fuel Rocket Engines by [Leroy J. Krzyck]. This book was originally written in 1967, but lathes and mills haven’t changed that much over the past 44 years. Why not give it a go? There’s still plenty of time to complete the build before the 100th anniversary of Goddard’s first flight.
We have been getting tons of emails lately recommending we take a look at various Kickstarter projects. We used to ignore them since they all boil down to a request for project funding, but since there are so many cool projects out there, we figured we might as well share a couple. Some of these projects have already met their funding goals, but we thought they were worth a mention anyhow.
Solar Powered Coffee Roasting
We’re all about both coffee and alternative energy, so this one caught our eye right away. While this coffee roaster won’t exactly fit on your back porch, it would be perfect for a coffee shop located in a sunny locale. Based off “power tower” solar concentrator systems, this rooftop-mounted solar harvester has big potential. Pair this with sopme sustainably-grown coffee, and you’ve got quite the tasty combo.
HexBright – an open source flashlight
What do you get when you combine milled aluminum hex bar and a Cree XM-L LED? A lightweight, extremely bright flashlight that won’t roll away on you. The HexBright puts out 500 lumens and sports a built-in rechargeable battery that can be topped off via your computer’s USB port. Not only that, the high-end version can be programmed to support any pattern or brightness that you choose. We’ll take two, thanks.
Arduino Project Board
[Randy Sarafan] of Clap-off bra fame is working on a slimmed-down Arduino board for use in the final stages of project development. He really doesn’t see the need to put an entire Arduino development board into his finished projects and often makes a quick perfboard circuit for his builds once he is finished prototyping. He’s grown tired of the process and developed a small circuit board that has all the connectivity he needs, without all the extra bits found on Arduino development boards.
The Large Hadron Collider was a success and it didn’t destroy the world. We have to admit, we were a little bit worried about the possibility of generating black holes but were soothed by scientists’ reassurances that we would still exist, and this self-explanatory website. We’re also kind of hoping to build our own. PHD Comics visits CERN to learn all about the experiment. Xkcd prepares for the end times with a new friend. The curious can explore some amazing imagery of the LHC, and read about the best-and-worst-case scenarios, and what scientists are hoping for, or monitor progress via webcam. The celebratory will listen to appropriate music, consume inspired science fiction, and drink to the Large Hadron Collider and its success.
Google Chrome made a huge splash in the past week, but will it really change the way you browse, and convince you to switch from your current browser? For those who want to play with it but don’t want Google to completely take over their lives, Chromium is the open source project behind Google Chrome. Linux and OS X users can also run Chrome using WINE, although success is not guaranteed. To make an educated choice, read Scott McCloud’s comic which explains the underpinnings. Make sure you’re aware of Chrome’s security vulnerabilities, and take advantage of Lifehacker’s guide to make your browsing experience as convenient and useful as possible. There are some great features, including the ability to log into multiple Google accounts using its much-lauded Incognito mode, which prevents Google Chrome from logging information on your browsing and downloading habits (websites you browse can still track your information). For convenience, you can also install Chrome on a USB drive, and take it anywhere with you. Explore the many Google Chrome blogs that have popped up to provide advice on hacking and tweaking the browser. Or you could just get all your information from 4chan.
FPGA’s have become especially useful to the hacker community of late. Once upon a time, these lovely pieces of dedicated hardware were fabled to only be within reach of deep pocketed graphics card producers working to up their shader and vertex counts. Today they’re often found in the bowels of high end network gear. As reprogrammable arrays of logic gates, FPGAs represent a happy middle ground between general purpose CPUs and dedicated silicon. After the break, we’ll recount some of the more interesting FPGA projects we’ve seen, like the open source graphics card we featured yesterday.
Continue reading “FPGA Projects Roundup”