It looks like we now have another way to annoy ourselves with extremely high voltage.
The bells operate under the same principles as the electrostatic see-saw we covered last month. A voltage is applied to one can while the other can is grounded. An insulated pendulum is placed between each can, and with a little coaxing can be made to oscillate back and forth between the cans. As the pendulum touches the charged can, it is repelled as it gains the charge and moves to the grounded can. There, the charge is released and the cycle continues again. A homemade Cockcroft Walton multiplier is used to generate the +35kV needed to get the pendulum moving.
[Ben Franklin] invented the Franklin Bells while he was investigating electricity in the 1750s. Originally an extension of the kite & key experiment, the bells were historically used to warn of approaching thunderstorms – when the bells rang, the atmosphere was charged and lightning could strike. Even though the voltage between the bells is huge, very little current is drawn – the Oxford Electric Bells have been ringing since 1840 using the same electrostatic battery.
Using our hands to manipulate game controllers is something most of us take for granted. However for quadriplegics, whose arms and legs are completely paralyzed, gaming becomes a nearly impossible task. One man has spent the last 30 years of his life trying to help quadriplegics once again “pick up” the controller and enjoy a few rounds of their favorite video games.
Retired aerospace engineer [Ken Yankelevitz] has been using his skills to create game controllers that can be easily used by disabled gamers, offering them for sale at cost. Starting with Atari joysticks in 1981, he has been perfecting his craft over the years, creating some 800 mouth-operated game controllers. As the systems and their controllers became more complex, so did [Ken’s] designs. His new Xbox and Playstation controllers use all manner of components, including sip-puff tubes and lip-activated buttons in order to allow users to access every single controller function.
Even as he approaches his 70th birthday, he is busy making controllers, though at a slower pace than he has in the past. He has said that he will continue making them for as long as he can, but at some point he will have to close up shop. This has disabled gamers worried that they may no longer have someone to turn to for custom controllers, though we hope someone steps in to fill the gap whenever that day comes.
Be sure to check out his site to take a look at his designs, what he has done for the disabled community is amazing.
Want to improve the finished look of your projects? There’s a lot you can learn by looking at the choices made in consumer electronics. [Bill Hammack] explores what is perhaps the most refined electronic device out there, the cell phone. Specifically, he discusses the seven design constraints that face every cellphone maker. They are: compactness versus usability, consumer preference, availability of energy, economic resources and available infrastructure, knowledge of materials, societal needs, and cultural constraints.
Anyone who’s whipped out their hacked-together project in a public space understands cultural constraints. Especially when forgetting your backpack in a public place can put the bomb squad of full alert these days. But aside from the anecdotal issues, [Bill’s] look at now-and-then cellphones really shows off the smart design that we enjoy thanks to the evolutionary process that went into what has become the wristwatch of the 21st century. See what he has to say in the video after the break.
Continue reading “Celebrating the design principles behind cellphones”
[LostSpawn] loves his clamshell keyboard for the iPad, but he had one major beef with the design. When the tablet is installed in the landscape orientation there’s no way to plug in a dock connector for charging or other uses. He pulled out the cutting tools and altered the case to meet his needs.
The case is a Rocketfish iCapsule which provides a Bluetooth keyboard when you need to do a lot of typing. The hard shell does a great job of protecting the iPad, but who wants to pull it out to charge it? The thing that we can’t believe is that there’s a slot milled in the other side of the bezel so that you can plug in headphones. How did they overlook the dock connector?
To add it himself, [LostSpawn] started by drilling a dotted line along the portion that he wanted to remove. He finished shedding material with a Dremel and then set about sanding it flat. To make sure it didn’t look too much like a hack he used Bondo to build up the working edge and then sanded and painted for a factory finish. Now he can plug in the cable or an SD card adapter like the one seen to the right of the keyboard.
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.
[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.
Continue reading “Simple clock uses RTC chip and character display”
[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.
Continue reading “Disappearing kitchen island”