Turning A Broken Bass Into A Headless Bass

January 11, 2013 by Brian Benchoff 5 Comments

bass

A while back [Michael] inherited a broken bass guitar from a friend. The headstock for this bass was cracked right down the middle, and the friend attempted a repair with a bolt and a couple of washers. After trying to figure out what the addition of a bolt was trying to accomplish, [Michael] set to work repairing this bass and ended up doing a headless conversion.

A headless bass, just as the name implies, does away with the headstock and moves the tuners to the other side of the guitar – in [Michael]’s case, right below the bridge. After sawing off the broken headstock above the truss rod, [Michael] made a string retainer and bolted it on to the remainder of the neck.

The tuners had to be moved, of course, so [Michael] routed out a section of the body below the bridge. Four holes were drilled and the original tuners slipped right in. The result is a perfectly functional bass that would fit right in to the tour van of an 80’s metal band.

You can check out [Michael]’s bass down in the pocket.

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A Really, Really Tiny Tube Amp

January 11, 2013 by Brian Benchoff 37 Comments

After building his first tube amp from a kit, he set to work on his next amp build. Since tube amps are a much more experimental endeavor than their solid state brethren, [Jarek] decided to make his next amp unique with military surplus subminiature tubes, and in the process created the smallest tube amp we’ve ever seen.

Instead of bulky 12AX7s and EL34s tubes usually found in tube amp build, [Jarek] stumbled upon the subminiature dual triode 6021 tube, originally designed for ballistic missiles, military avionics, and most likely some equipment still classified to this day. These tubes not only reduced the size of the circuit; compared to larger amps, this tiny amplifier sips power.

The 100+ Volts required to get the tubes working is provided by a switched mode power supply, again keeping the size of the final project down. The results are awesome, as heard in the video after the break. There’s still a little hum coming from the amp, but this really is a fabulous piece of work made even more awesome through the use of very tiny tubes.

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Letting [Euler] Help Out With PCB Fabrication

January 11, 2013 by Brian Benchoff 20 Comments

drillin

Since [Alessio] has been etching his own PCBs, he’s hit upon the most tedious part of the process, and the reason homebrew SMD boards are so awesome: drilling your own boards is a pain. While [Alessio]’s CNC mill takes care of most of the work, aligning the pre-drilled boards and correcting for any scaling issues from the mask is a bit difficult. With the help of a transform matrix, though, drilling PCBs has never been easier.

While the Gcode running the mill may be accurate, the actual manufactured PCBs might not be. If the extents on [Alessio]’s board aren’t exactly aligned with the axes of the CNC mill, the drill holes end up where they’re supposed to be. To solve this problem, [Alessio] wrote a PCB drilling transformational matrix calculator. The basic idea is by drilling just a few holes, [Alessio] is able to calculate any offset required in the Gcode with the help of a little bit of linear algebra.

Peltier Campfire Generator Put Out 14W (kind Of)

January 10, 2013 by Mike Szczys 47 Comments

peltier-campfire-generator

This is the control and monitoring hardware which [Jack] built for his campfire electricity generator. He’s done an amazing job to get this far. You can see he’s pulling 1 Amp at 14.2 Volts off of the system. But there one gotcha that’s still plaguing him.

The rig uses a big metal plate as a heat sink over the campfire (which is simulated by a cooking stove for testing). On the back of that plate is an array of Peltier coolers which generate electricity based on the temperature difference from one side to the other — it’s the same theory behind candle generators. The cold side has a heat sink with water running through it. What you see above are three relays which switch between using the Peltiers in series or in parallel based on their voltage output. You can’t really make it out there but there’s a radiator and recirculating pump to the right which are used to cool the water. The gotcha we mentioned is that the radiator can’t quite keep up with the heat of the fire. To get the results seen above [Jack] is running cold water from the tap through the radiator. But maybe if this were used in the winter the water could be circulated through a big box full of snow. Just keep shoveling it in to keep up the electrical potential!

After the break we’ve embedded part four of the project video as it shows off the array of peltier coolers quite well. You will also see part five (radiator and recirculating pump testing) from which this image was taken.

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Prototyping A Low-resolution Handheld Gaming Rig

January 10, 2013 by Mike Szczys 9 Comments

low-res-arduino-gaming

[Jason] has been hard at work on this Arduino-based low-res gaming platform. He even had a fab house deliver circuit boards to pull everything together. It’s a little small in his hands, and the graphics are limited to the 8×8 pixels provided by the display. But it still looks like a lot of fun and the code was written to make adding new games quite painless.

The board hosts an ATmega328 which drives the bi-color LED display using a pair of TPIC6B595 shift registers. Control is provided by a collection of buttons to either side of the display. The unit is powered by three AAA batteries held in a pack soldered to the back side of the PCB.

The image above shows [Jason] giving a Space Invaders game a try. The clip after the break shows respectable action, sound from a piezo buzzer, and it even scrolls your score at the end of the game. But you’re not limited to just one title. Adding new games is as easy as implementing a class in a new header file. You can get a feel for how this is set up by viewing the source code repo.

This reminds us of the Pixel Bros low-res system.

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One-button Scan To Email Using Raspberry Pi

January 10, 2013 by Mike Szczys 7 Comments

We’ve come across extremely expensive photocopiers that also fax, scan to email, and generally have too many features to list. [Eduardo Luis] figured out how to implement some of this type office magic using very inexpensive components. Specifically, he can press one button to scan a document and send it to an email address.

The user controls patch into the RPi GPIO header. There’s the button we already mentioned, a red LED for “System Busy”, and a green one for “System Status”. A set of scripts montor the button and drive the LEDs. When it’s time to scan, the RPi uses the scanimage package to capture a .PNM file, then converts it to .JPG before sending it via email using the mutt package.

We’d love to see a character LCD and a few more buttons added to the setup. This way you could select between different recipients (or even send via fax). And there’s always the possibility of connecting a printer to the other USB port on the RPi to make it work as a photocopier too.

You can catch a demo video after the jump.

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Motorized Binocular Chair Has You Stargazing In Comfort

January 10, 2013 by Mike Szczys 30 Comments

motorized-binocular-chair-for-stargazing-in-comfort

It seems like something out of The Red Green Show but this motorized stargazing chair is a serious piece of astronomical hardware. It has a shelf that places a set of high-power binoculars directly in the user’s line of sight. The elevation is easy to adjust. And a power drill lets you take the whole thing for a spin.

The base has been outfitted with cogs and a chain from an old bicycle. The gear reduction lets a power drill rotate the platform. This worked well enough but [Gary] found that making fine adjustments was rather difficult and more often than not he ended up moving the binoculars to avoid overshooting when adjusting the platform with the drill. Luckily he didn’t give up on the idea. On the eighth and final page of his build log he refines the rotating setup with the help of an ice cream maker. It’s gear box is used as a speed reducer so that a very slow drill speed results in an extremely small heading correction. Now he can view the stars in peace, freed from frustration by a well-refined hack.