Building Your Own Mini Fridge?

April 3, 2015 by James Hobson 58 Comments

Ever play with a Peltier plate? They’re these really cool components that kind of look like a ceramic sandwich, and when you put power into them, one side gets hot, and one side gets freezing cold! [Joseph Rautenbach] decided he wanted to try making his own mini fridge out of one — which is typically how most modern mini fridges work these days.

The peltier plate he’s using draws 12v at about 3.5 amps — so about 50W — and if you don’t heat sink it properly you could burn it out in a matter of seconds. Peltier plates only care about the temperature differential between the two sides — if you don’t take the heat away from the hot side, it will soon overheat and destroy itself.

[Joe’s] using a styrofoam cooler for the fridge with a pair of computer heat sinks and fans for the peltier plate, and a temperature PID controller he bought off eBay. The external heat sink sucks away the excess heat generated by the peltier plate, and the internal one helps spread cooled air around the inside of the styrofoam cooler. The PID controller allows him to set a preferred temperature to maintain in the box, which will then control the outputs to keep it that way.

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Help! There’s An Imp In My Coffee Pot!

March 22, 2015 by James Hobson 20 Comments

Coffee. The lifeblood of our society. The sweet nectar of bean, whose chemical compound makes us feel so, so good. Doesn’t it deserve a place in the Internet of Things? [Matt] and [Don] thought so — so they connected their old coffee pot to their phones.

After receiving their developer version of the Electric Imp board, the two started thinking of small projects to test it out on; ones that might even have a real-world application. Since the Imp is capable of receiving inputs via the web, it’s super easy to write an app to control things — in this case, a coffee pot.

Hardware-wise it was actually pretty simple. The coffee pot control board provides power for the Imp, and the On/Off switch of the coffee maker is wired to one of the Imp’s outputs. One simple app later, and boom we have wireless java capabilities. Heh. Java.

Continue reading “Help! There’s An Imp In My Coffee Pot!” →

Caramelizing Sugar With A Laser

March 4, 2015 by James Hobson 20 Comments

If you happen to have access to a laser cutter, you’re bound to try cutting or engraving something it wasn’t designed for. We know we have. [Bonnie] and her friend [Brenda] decided to try something new — caramelizing sugar with a laser.

At their local hackerspace, NYC Resistor, they brought in some chocolate squares and colored sugar and started tinkering with the laser. It’s a 60W CO2 laser by Epilog. After testing a few different options they ended up with the following setting for optimum sugar caramelizing with only one pass:

Speed 100
Power 30
DPI 300

By spreading a thin layer of sugar over top of the chocolate, you can effectively melt and bond the sugar to the chocolate — we suspect playing with the laser focus will also help you fine tune the process for your own confections.

You could just etch the chocolate with the laser as well — but that’s not quite as cool. Perhaps try to up your sushi game, why not laser engrave seaweed before rolling? Or make the perfect laser-cut gingerbread house thanks to designing it in CAD?

Choctopus Chocolate Printer X8

January 14, 2015 by Matt Freund 14 Comments

Valentine’s Day is about a month away, long enough for everyone to ~~butcher~~ upgrade their 3D printers to squirt out chocolate. Food printing was a hot item at this year’s CES, but it is hardly new. Before many of you were born [Hans] left his job at the Council for Scientific and Industrial Research to produce chocolate out of his garage in South Africa. This one prints 8 at a time!

Many years before he was extruding lawnmowers from raw pellets, [Hans] built the 8-tentacled Choctopus. He gets away with using only one chocolate pump – from some experience, by far the most challenging component – by simply splitting the ooze pipe with three tiers of T intersections. The whole design is actually patented and revolutionary for 19 years ago but to our readers probably unremarkable.

There is a business lesson here too. Once upon a time the Choctopus was a 3D printer but economic constraints have led to him downgrading to 2D. Any 3D requirements are served from an alternate RepRap. The purpose of an 8-armed printer is to mass produce, but for the price, most clients were only interested in a one-off. The products that pay the bills are the much more affordable 2d extrusions in bulk.

Any of our readers looking to ~~impress their date~~ make lots of money next month, consider this the kick in your pants to get started.

Check out these videos of the Choctopus churning out delicious delicatessens.

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This Cake Is Not A Lie

December 31, 2014 by James Hobson 8 Comments

Introducing the world’s first(?) edible and interactive RGB matrix cake — the ArCake.

[Treibair], one of our readers from Germany was inspired a few years ago with the LED cake we made here at Hackaday. Ours used angel food cake squares that allowed LED lights to shine through the squares from underneath the cake, where the LEDs are housed in the technologically advanced cake tray. It worked pretty well but we didn’t exactly recommend people to follow in our foodsteps.

That didn’t stop [Treibair] though, and he came up with his own unique twist on the cake! Instead of bothering with various cubes of angel food cake, he had a much more direct method.

It’s easy to do, just follow these steps:

Drill some holes in a cake
Put your jello in that cake
Make her open the box

And that’s the way you do it.

The resultant LED diffusers let lots of light through, while retaining their most important quality — tastiness. All in all, he made 30 jello filled holes which allowed him to place a 5 x 6 LED matrix underneath the cake. Now when he gives the cake to his wife, it will read her a Happy Birthday message, and then allow her to play a Jump’n’Run game using a Wii nunchuck controller!

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Dead Simple Hack Allows For “Rebel” Keurig K-Cups

December 10, 2014 by Rick Osgood 141 Comments

If you haven’t actually used a Keurig coffee machine, then you’ve probably at least seen one. They are supposed to make brewing coffee simple. You just take one of the Keurig “k-cups” and place it into the machine. The machine will punch a hole in the foil top and run the water through the k-cup. Your flavored beverage of choice comes out the other side. It’s a simple idea, run by a more complex machine. A machine that is complicated enough to have a security vulnerability.

Unfortunately newer versions of these machines have a sort of DRM, or lockout chip. In order to prevent unofficial k-cups from being manufactured and sold, the Keurig machines have a way to detect which cups are legitimate and which are counterfeit. It appears as though the machine identifies the lid specifically as being genuine.

It turns out this “lockout” technology is very simple to defeat. All one needs to do is cut the lid off of a legitimate Keurig k-cup and place it on top of your counterfeit cup. The system will read the real lid and allow you to brew to your heart’s content. A more convenient solution involves cutting off just the small portion of the lid that contains the Keurig logo. This then gets taped directly to the Keurig machine itself. This way you can still easily replace the cups without having to fuss with the extra lid every time.

It’s a simple hack, but it’s interesting to see that even coffee machines are being sold with limiting technology these days. This is the kind of stuff we would have joked about five or ten years ago. Yet here we are, with a coffee machine security vulnerability. Check out the video demonstration below. Continue reading “Dead Simple Hack Allows For “Rebel” Keurig K-Cups” →

An Engineer’s Guide To Cooking The Perfect Turkey

November 26, 2014 by Sarah Petkus 21 Comments

It’s almost that special time of year again where we all get together and use our families as guinea pigs for new cooking techniques and untested recipes! Some of us are seasoned pros at preparing the big bird of tradition, while others are still experimenting year after year with hopes of nailing the optimal method by chance. [Travis Mikjaniec] approaches this culinary conundrum from an engineer (of aerodynamicist)’s perspective, with the goal of scientifically discerning through simulation the best method to prepare a Thanksgiving turkey; no long term trial and error required.

As the basics of cooking dictate, the rate at which the meat of a turkey will cook is determined by where the hot air is flowing and gathering inside the oven. Areas of the bird subjected to consistent fresh heat will cook faster and are more likely to dry out over time, so it’s important that the hot air is equally dispersed for an evenly cooked, juicy turkey. To figure out the trajectory of the air and the point where it begins to cool down, [Travis] modeled the naked bird in CAD, complete with the hallow cavity within. He then recreated the baking conditions to use in FloEFD, in this case a standard convection oven with a fan located in back. To compare cooking techniques against one another, he ran a series of streamline simulations with combinations of different cooking variables, like how high the bird was lifted off the baking sheet and whether or not the inner cavity had the added thermal mass of stuffing or not. These chaotic diagrams of simulated air flow helped visualize which conditions were conducive for even heating.

If you’re interested in knowing the verdict of [Travis’] trials with virtual turkeys, he offers thorough documentation on his investigative blog post. His insight might help improve your cooking game plan for Thanksgiving or teach you something you didn’t know about the aerodynamics of a fifteen pound headless bird… which is something you can talk about while sitting around the table.