Restoring Yellowed Computer Plastics

March 2, 2009 by Eliot 39 Comments

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Many of our cherished computers and consoles from the past have not stood up well over time. It’s not the hardware as much as the color. From Commodores, Apples, to Super Nintendos, the machines have slowly drifted towards a sickly yellow and even brown. The culprit appears to be the fire retardant chemicals used in the plastics. Amiga enthusiasts have spent the last year perfecting a technique that restores the plastic of these machines to its original splendor. Dubbed ‘Retr0brite‘ it’s a gel made from hydrogen peroxide, xanthan gum, glycerine, and ‘Oxy’ style laundry booster. The results are really impressive. If you do start restoring your own machines, caution should be used since it requires strong concentrations of hydrogen peroxide typically employed in bleaching hair.

[via Waxy]

Parts: 32KB SPI SRAM Memory (23K256)

March 2, 2009 by Ian 15 Comments

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Microchip’s new 23K256 is a serially interfaced 32 kilobyte SRAM memory chip, available in 8 pin DIP and 8 pin SO packages. SRAM, like EEPROM, is a data storage medium. Data stored in SRAM is lost without constant power, but it’s really fast and there’s no limits to the number of write cycles. EERPOM stores data even without power, but it’s slow and usually limited to around a million write cycles.

32K SRAM chips typically have 15 address lines and 8 data lines, like the IS61LV256AL we used on our CPLD development board. The 23K256 requires just four signal lines, but sacrifices the speed of a parallel memory interface. It’s a great way to add extra memory to a low-pin count microcontroller without routing 23 signal traces. We’ll show you how to interface this chip below.

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Paintball Gun Turret

February 26, 2009 by Eliot 39 Comments

[Jared Bouck] has been sending in his projects for a couple years now. We’ve enjoyed his heavy-duty DDR pads, LCD backlight repair, and ion cooling projects. His latest, an RC paintball gun turret, is our favorite though. He actually rates this as one of the easier projects he’s published; it just took a while to assemble. Several design decisions were made to keep the project simple. Two 32 Degrees Icon-E paintball guns were used. The guns already have electric solenoids for firing, so a special trigger mechanism didn’t have to be fashioned. Q-loaders were used to prevent any ball feed problems. The motors, driver boards, and RC components are all borrowed from combat robots for reliability. He’s hoping to produce a small number of kits based on this design.

Related: We’ve got quite a few sentry gun projects in the archive.

Experiments In Polaroid

February 20, 2009 by Caleb Kraft 16 Comments

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[Peter] found that Polaroid film was an easy medium to play with, as the ability to develop it is built in. He has done several fun experiments, from electrocuting it to making giant mozaics. The Polaroid film may not be easy to get your hands on though. They stopped producing it in the summer of 2008. Some former employees are trying hard to get it back into production, but that may never happen. Polaroid has recently received permission to sell itself at auction. We’ll just have to wait and see.

Temperature Sensing Munny

February 18, 2009 by Eliot 7 Comments

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Here’s another nerdy present that was built for Valentine’s Day. [João Silva] created a temperature sensing Munny. A Munny is a vinyl toy made to be customized. Other than these Munny speakers, we haven’t seen them in many electronics projects. The LM35CZ temperature sensor has an analog output that connects to the ADC on the ATtiny15L. The microcontroller changes the RGB LED’s color based on the temperature: blue for cold, green for comfortable, and red for hot. It only flashes every three minutes to conserve the power in the coin cells. His one-off circuit board also includes an ISP header for programming. The Munny’s head looks like it does a great job diffusing the light.

Molten Metal LED Display

February 16, 2009 by Caleb Kraft 19 Comments

[youtube=http://www.youtube.com/watch?v=gMuDudCiPR8]

firstly, we don’t know why they are doing this, and we don’t care. You are watching an LED panel, controlled by molten metal. The panel has the leads sticking down below the bottom of the board, so the metal can make connections as it flows past. They are using Wood’s metal, not mercury so it has to be heated to about 159 degrees Fahrenheit to be fluid. This has been representing problems as the metal tends to stick to whatever container he is holding it in. That actually seems to be what most of the writeup and discussion are about, rather than, what it will be used for.

[Thanks Andre]

Flexible Circuit Valentine

February 14, 2009 by Eliot 11 Comments

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[xander] built this LED valentine for his loved one. It’s interesting because he used Pyralux, a flexible circuit board material from DuPont. He describes the consistency as “tough plastic tissue-paper”, but had no trouble using standard toner transfer etching. It has an ATtiny45 microcontroller that pulses the 16 LEDs at an approximation of his heart beat. To avoid soldering a bunch of surface mount resistors, he used two constant current shift registers.