Nixie Clock That Doesn’t Skimp On The Number Of Tubes

November 2, 2012 by 21 Comments

[Nina Blum] figures that if you’re going to the trouble of driving Nixie tubes you might as well use a lot of them. The details about this clock, which were sent directly to our tips line, lists a total of thirteen tubes used. There are six Russian IN-8 tubes (large digits), four Z573M tubes (small digits), but the colon tubes and the sine wave tube part numbers were not specified.

An ATmega8 controls the segments via a set of transistors. To operate the display [Nina] included a user interface made from five buttons and a four line character LCD. There is a video showing off the menu system that includes a way to set the time, date, and toggle the various illuminated bits. We’re waiting for permission to post that clip on our YouTube channel as [Nina] only included a Rapidshare link to the movie. Right now you’ll find more images after the break and we’ll embed the video if we get to okay.

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Computers Not Candy With The Geek Group

November 2, 2012 by 20 Comments

This year for Halloween, The Geek Group, decided to take a very different approach to outreach. Instead of making animatronics, or converting their giant (seriously HUGE) space into a haunted house, they held an event called “Computers Not Candy” where they teamed up with a large local company to bring 100 tablet computers to 100 youths.

If you’re not already familiar with the Geek Group, you should check them out. They’re a huge hackerspace that really seems to have their act together. They put out really cool videos regularly, our favorite being the equipment autopsies.

While we really do admire the work they did to introduce these kids to hackerspaces, we also love candy and silly spooky projects. Next year how about Computers AND Candy!

Pull-string Most Useless Machine

November 2, 2012 by 18 Comments

The mechanical simplicity of this pull-string controlled most useless machine is delightful. You can see the metal gripper which is reaching up to tug on a light-fixture-style pull chain. This is how it turns itself off after you’ve pulled the string to power it up.

The device is [Alex555’s] entry in the 7400 Logic competition. We do hope that he ends up posting a schematic because we’d love to see the gritty details of how it works. After the break you can watch two doors open, allowing the arm to raise up and the gripper to grab the chain. This takes just four servo motors, which are controlled by the signal from a 555 timer and some accompanying hardware.

Apparently the chain is a fake, as the servos didn’t provide enough force to actuate that type of switch. It’s not a surprise as those pull chains do require quite a tug. An optical sensor was used to trigger the movement when your hand reaches for the chain.

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ATmega1284 As An 8-voice 32 KHz Synthesizer

November 2, 2012 by 10 Comments

A couple of things strike us about this 8-voice 32 kHz synthesizer. First is the cleanliness of the prototype. As you can see, each part has plenty of room on its own board and all are interconnected by 10-pin IDC ribbon connectors. But you’ll have to see the video after the break to enjoy the impressive sound that this puts out. You’ll hear it play the Super Mario Bros. theme; it does it with passion!

To get audio from the digital microcontroller [Mike] built his own R2R digital to analog converter. The resistor ladder is built from sixteen resistors, which feed a rail-to-rail amplifier. The sound is mono but the playback is polyphonic thanks to the work done by the ATmega1284. It is reading MIDI commands coming in from an external controller (we assume it’s the computer on which the hardware is sitting). The chip’s 128 KB of Flash memory leave plenty of room to store samples, which are selected from a lookup table based on the MIDI data. If more than one sample is to be played the chip averages the data and sets the 8-bit output port accordingly.

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Building A 100 MHz Frequency Counter

November 2, 2012 by 5 Comments

The great thing about building with gates is the crazy speeds you can achieve by using hardware directly (as opposed to working with simple microcontrollers). This 100 MHz frequency counter is a great example. [Michael] just finished building it using a Papilio board.

Of course we’re not talking about discreet chips here. The Papilio is an FPGA development board which means he is building with hardware gates, but that is still done by writing code. Above, the rig is measuring a 25 MHz being generated by a second FPGA board. Using the Papilio’s on board 32 MHz clock the device is capable of counting a frequency up to 100 MHz. You can see it measuring a 96.875  MHz signal in the video after the break. One interesting thing about that clip is that near the end he touches the crystal’s case with his finger and the Hertz really jump for a moment.

If the 8-digit display looks familiar that’s because [Michael] recently published a library to use it with an FPGA.

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Laptop Motherboard Reborn As A Low-wattage Server

November 2, 2012 by 52 Comments

[Darknezz] sent us a set of photos and some details about his damaged laptop motherboard turned into a server. A client brought him a Dell 1525 on which nothing was showing up on the LCD screen. The HDMI and VGA still worked, and he traced the problem to no signal coming out of the motherboard. He swapped the board out to get the laptop working again, but he client said he could keep the damaged one.

It has a dual-core CPU which meets his needs and since it’s meant to run off of a battery it’s as energy-efficient as possible. [Darknezz] dug through his parts bin and found a PSU that could supply the needed 19.5V at 3.5A. The connector didn’t match but it didn’t take him too long to patch into it using a spare Molex connector. He also needed a power button and ended up soldering a momentary push switch to a couple of pads which he traced out form the original connector. The only thing he actually ended up purchasing were the memory modules. Check out the photos he took of the alterations in the gallery after the break.

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Turning A 600 Mil Chip To 300 Mil

November 2, 2012 by 75 Comments

We’ve seen a few builds featuring NXP’s LPC1114 microcontroller before. This chip – the only breadboard friendly ARM microcontroller available – comes in a ‘still a little too large for prototyping’ 600 mil, 28 pin package. We won’t hazard a guess why NXP chose this rather large package, but the good news is it’s possible to shave this chip down to the more common 300 mil, 28-pin package used by AVRs and PICs.

In the video tutorial of this procedure, the chip is first taped down to a desktop CNC mill. 150 mil on each side of the die are removed, exposing the very cool-looking pattern of leads coming out of the chip. This isn’t enough area to solder, so the chip had to be further milled to expose some of the internal wiring.

After soldering everything to a set of pins, the new 300 mil package is covered in epoxy putty, milled down again into a nice cube shape and painted. Yes, the modified chip does work, and no, we can’t figure out why NXP chose a 600 mil package for this microcontroller over the far more common 300 mil chip.

Video after the break. Tip ‘o the hat to [Ian] for sending this one in.

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