Adjustable Voltage And Polarity Tester

polarity_tester

Instructables user [Rudolf] wrote in to share a handy little tool he created with ham radio operators in mind. Now and again, he found himself connecting to an unknown power supply, and rather than blow out all his expensive radio gear, he decided to put together a simple polarity and voltage tester that can be easily carried out in the field.

The tester features a pair of powerpole connectors, which are used quite often for connecting HAM gear. A PIC12F675 runs the show, acting as an adjustable comparator for detecting voltage levels. By default, his probe glows amber when the supply voltage is below 11.5V, turning green when the supply is between 11.5V and 15V. When the detected voltage is too high, the built-in LED glows a bright red. When the polarity is reversed, the LED flashes red regardless of the supply voltage.

All of these trigger levels can be set in the PIC’s code, which [Rudolf] is kind enough to include on his page, along with schematics for making your own.

Simple Clock Uses RTC Chip And Character Display

[Giorgos Lazaridis] just finished building a simple clock on a breadboard. It uses a common real time clock chip, the DS1307. This is less expensive that its full-featured older brother, the DS3232. The difference between the two is that the 1307 requires an external 32.768 kHz crystal and it is not temperature compensated. This means it will not be quite as accurate over the long-haul (it may wander as much as one minute per month), but it still blows the accuracy of using a microcontroller as an RTC out of the water and includes a backup battery which will keep time when the rest of the circuit is switched off.

This design uses a PIC 16F1937 to display the time and date on a 16×2 character LCD screen. Six buttons are dedicated to incrementing one specific chunk of data (ie: one button changes the year, another the day, etc.). A seventh button can be held down when using the other six in order to decrement the setting. We’re always interested in how the button code is written. [Giorgos] did share his code, but he wrote it in assembly so it’s of little use to us as we tend to stick to C code.

See the walk through video after the break.

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Disappearing Kitchen Island

[Tim Thaler] has been redoing his home, adding some fancy automation here and there. But when it came to the kitchen, he went all-out by installing an iPhone controlled disappearing island. In the video clip after the break you can see [Tim] dial up some extra counter and storage space from his smart phone. One click causes it to slowly rise from the depths, shedding the carpet tiles as it goes.

Directly beneath the kitchen is an unfinished storage room. [Tim] framed a hole in the floor above, and sourced a used scissor lift for about $380 to do the heavy lifting. It operates smoothly and isn’t all that loud. It sure makes for an interesting feature if he ever decides to sell the place.

We thought it was a nice touch that the storage room hiding the mechanical parts of the hack has a hidden entrance. You must travel through the billiards room in the basement to access it, turning the ball rack to unlatch the entrance.

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Thirty Year Old Pachinko Machine Meets An Arduino

When [Jim’s] thirty year old Pachinko machine started to freeze up and shorted out his computer’s graphics card he decided it was time to replace the old electronics with an Arduino. Originally the Pachinko machine ran off a 48 volt supply and control was achieved using about 20 relays, the random numbers were generated using some complex mechanical reels which we hope will find their way into a new project in the future.

All of this and the daunting amount of wire inside the machine have been replaced with an Arduino and an MP3 Shield for the sound effects, powered from a much safer 12 volts. The new machine runs just as you would expect a thirty year old machine to run, with all the grinding sounds and flickering lights. Check out the video after the break to see an overview of the project.

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Blox That Play Back

I’m sure most of us remember playing with blocks when we were kids, well now this age old children’s toy has been crammed full of electrical goodness by a team of Electrical Engineers from the University of Texas. The Blox, which are about the size of a standard Rubiks Cube each contain 16 IR sensors, 4 touch panels, a 3-axis accelerometer, a ZigBee Wireless Module, a 2″ OLED display and a battery, all controlled using an ARM Cortex processor.

The Blox show their full potential when used together as an interactive distributed computing system. Blox is an open source project so all of the build details, schematics and code can be found on the website. For an overview and demonstration of the Blox check out the video after the break.

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Bikinis Of The Future!

bikini_duo

It’s always interesting to see what happens when hacking meets clothing – check out this pair of bikinis, for instance.

This first item, called the N12 bikini (mildly NSFW), comes from Continuum Fashion and is composed entirely from Nylon 12, hence the name. Shapeways uses 3D Selective Laser Sintering (SLS) to create the tiny circles that make up this piece of swimwear. The suit is held together by tiny stretchy strings made of the same nylon, and the bikini can be printed to order. It seems like an interesting idea, but we wonder how it would hold up against some big waves or a game of beach volleyball.

The second item is a bit more functional. Designer [Andrew Schneider] has put together a bikini that can solve all of your energy needs while sitting by the pool. His solar bikini is covered with hand-sewn flexible solar cells that work together to produce up to 5v, available via a USB connection. He claims that you are free to go swimming in the suit, so long as you dry out the USB port before using it again. For all the guys out there crying foul, don’t worry – he’s got a suit for you too. He’ll be putting together a men’s suit in the near future that powers a 1.5 amp Peltier cooler to keep your beer cold – we just don’t want to know where the hot side of the Peltier goes…

Puppy POV: Four-legged Persistence Of Vision Display

puppy_pov

We see lots of persistence of vision projects around here, but we can’t recall any that involve a POV display facilitated by a living, breathing animal (humans aside, if you want to picky). [Michael] has a Miniature Pinscher that just loves to run and run…and run…in circles. Since she generally runs very fast and in large curves, he thought she would make a great POV device.

He has a small fleece “jacket” for his dog, and on it, he mounted a Lilypad Arduino, the associated power supply, and five bright white LEDs. Naturally, conductive thread was used to wire up the circuit, and after a bit of trial and error, things came together nicely.

With the vest complete, [Michael] unleashed his dog at the park, letting her run to her heart’s content. All the while, her vest was writing out [Cory Doctorow’s] “Makers” while he snapped some pictures.

We can’t think of a more appropriate text to write with LEDs in the night, but in the spirit of the book, we were hoping to see a circuit diagram or the project’s code posted. If he shares it, perhaps we could convince [Cory Doctorow] to run about the park in a vest, writing out [Michael’s] code in bright white LEDs!