This neat accelerometer controlled marble maze adds a level of fun to retrieving a gum ball. You have to first navigate the maze using a controller that has a dual axis accelerometer in it to control the angle of the platform. Though that does look like a wii accessory, there is no wiimote in there.  Only after you have completed it will the gum ball machine dispense the candy. [Dan] constructed everything himself, which might explain the lack of “pits” for the marble to fall into in the maze.

More details on the build and source code are available on his page.

[via hacked gadgets]

[Jack] wrote in to let us know about a project that creates a virtual microprocessor core based on the ATmega103 by using a Field-Programmable Gate Array. Great, we thought. Here’s another rather esoteric project like the NES on a FPGA, but what’s the motivation behind it? We asked [Jack] and he provided several scenarios where this is quite useful.

Implementing the AVR core allows code already written for the chips to be easily ported to an FPGA without a code rewrite. This way, if your needs outpaced the capabilities of the microcontroller long after the project has started, you can keep the code and move forward from that point with the added capabilities of the gate array. Having the core already implemented, you then only need to work with HDL for the parts of the project the AVR was unable to handle. He also makes the point that having an open source AVR core implementation provides a great tool for people already familiar with AVR to study when learning VHDL.

With products like the Butterfly that this project is based around, or the Maple we’ve seen in the past, programmable logic for the recreational hacker is starting to get a little easier.

[Chris] wanted a guitar with a keyboard but didn’t want a keytar. Like any good hacker he took a cheap guitar and a small keyboard and introduced them to each other. He moved the control knobs to make room for the keyboard and added the control circuitry from the keyboard to the top of the guitar’s body. A 9v battery is used to power the keys and something called “Chris Collins’ transformer trick” is used to amplify its sound. If you know details on this transformer, leave a comment and we’ll update the post. Take a look at the video after the break to see [Chris] perform the Final Countdown on keys and guitar.

The guitar is a Chinese made Telecaster clone and we think he’s the first one to find a realistic use for keyboards that don’t use full-sized keys. [Chris] apologizes for the lack of build photos but we give him a pass; he lost his phone while crowd-surfing and that’s as good an excuse as any for losing some pictures. We can’t wait to see another performance with this gnarly axe once he’s had enough practice to pull everything together!

Today we stumbled upon [jimthree's] Seismic Reflector while looking at projects that employ the Processing language we mentioned a few days ago. Utilizing a Boarduino and some vibration motors from a game controller, the Seismic Reflector does just as its name implies – rattles itself around whenever there is an earthquake. While this does seem a bit silly at first, we were fascinated to learn there have been 165 earthquakes just in the past week and almost no news reports, suddenly this device got a lot more interesting!

[Texane] wrote in to let us know he has implemented AVR ISP programming using a PIC microcontroller. He wrote some code for an 18F4550 that uses the STK500 standard for In System Programming. This means that his hardware is compatible with AVRdude, the open source AVR programming software. There has long been an argument over the virtues of PIC versus AVR but we say why not both? If you have already honed your programming chops with PIC, you can build your own programmer and give the Atmel family a try.

The current implementation uses a serial port to connect the programmer to a computer. Keep your eye on this one as [texane] plans to add USB connectivity and has told us he will post schematics for the device as soon as that is complete.

Optical encoders are nothing new; they can be found in everything from mice to printers. They’re great for allowing DC motors to know their exact position and even current direction. If this is sounding like old hat, it’s because we’ve shown you rotational versions before.

[Chris] uses the same concept, but produced a linear optical encoder instead of rotational. His setup is much like whats used in non stepper-motor CNC and RepRap mills, allowing ordinary DC motors to know their position within a plane. It’s a quick tutorial, but we liked the detail and it reminded us we need to finish that DC motor based mill thats still a pile of parts in the closet. Check out a video of [Chris'] in action after the break.

Slow day at the office?  Here’s a trick that’ll make your coworkers smile. Dangerously Fun has a guide to build a homopolar motor from a battery, copper wire, and magnet. A homopolor motor doesn’t rely on electromagnets in an armature changing their polarity to force a rotation movement compared to stationary magnets. Instead, they use an electrical current’s orientation to a magnetic field to provide a repulsive or rotational force.  In this implementation, the current moves through a loops of copper wire from one pole of a battery to the other.  A rare-earth magnet on one pole of the battery provides the magnetic field.

After the break we’ve embedded video of this simple example as well as a few more complex homopolar examples such as a five speed version.  The motor in action certainly brings a smile to our faces and places this firmly in the useless machines family of hacks.

Oops, this next one’s NOT a homopolar motor.  Thanks Fallen.

[Thanks Paine]

[Keith Baxter] has undertaken something of a ‘Mount Everest’ of guitar modifications. He’s developing a Servoelectric guitar that trades frets for a keypad. It is still a guitar in the sense that it has a body, strings, and pickups to sense the strings vibrations and pass them to an amplifier. The left hand, which traditionally would shorten the strings as needed by pressing them against a fret, now changes string pitch using a keypad. This is an interesting fusion between traditional guitar and 80’s phenomenon, the keytar.

Each string is connected to a different servo motor. When a key on the keypad is pressed, the corresponding servo adjusts the tension of that string, bringing it in tune at the new pitch. His original design involved a lot of custom circuitry but he’s evolved the project to include an Arduino controller. This second generation both simplifies the control circuitry and improves upon it.

We’ve embedded some video after the break. In the first example you can see the strings adjusting for each new pitch. In the second, take a look behind the guitarist… what do you think he’s got planned for those giant capacitors?

Warning: This video contains actual footage of a severed dog head, kept alive. Watch at your own peril.

[Annalee] over at io9.com has gathered together the 25 scariest science experiments.  There are some truly frightening pieces, like the cyborg beetles which we’ve seen before, all the way to silly stuff like the guy who re grew his thumb using pig powder. Next time you’re thinking of admonishing someone for creating a flamethrower, or a super fast scooter, consider for a moment that they’re not burning peoples nasal passages to stop masturbation or creating zombie severed dog heads like the one in the video above.

Sometime the projects you see at the local hacker space are better left a secret when you return home for the evening. Case in point, this ping-pong ball launcher that can put holes in a sheet of OSB. The projectile is made more lethal because the ball has been injected with water to dramatically increase the density. Compressed air is used to propel it from the 14 round magazine with devastating effect.

We’ve embedded a video of the gun being fired after the break. The creator, [Ron Kessinger], demonstrated this at a Denver hacker space called Club Workshop. We’re hoping there’s no plans for turret automation because this thing’s dangerous! Either way, the significant other who usually watches out for our safety would never approve.

We’ve all been there; hardest decision we’ve ever had to make. College and debt or freedom but no career? Start a family or live out alone? The number 2 with a small shake or side of fries?!

[Leon] sent in his random number generator, oddly enough not to just generate a number, but help us through with those life altering decisions. Using a noise diode like setup he’s able to generate random bits, which an ATtiny24 then converts and displays on a 7 segment LED. His generator also has the ability to set upper and lower limits. Seems like an awful lot of work to avoid the freedom of choice paradox, but we enjoyed the project none the less. Check out a video after the break.

Darpa has another contest coming up. You may remember some past Darpa competitions, like the 2007 Urban Challenge. Where hackers, engineers, and scientists alike came together to build autonomous vehicles. The game this year is to celebrate the 40th anniversary of the Internet.

The rules are simple enough, find a bunch of red balloons and mark their latitude and longitude. The hard part? There is only 10 balloons – spread across America. It will take an extreme amount of social network engineering, but it all pays off with first place receiving $40,000.

[Viacheslav] wanted his virtual terminal to have the look of a DEC VT220. He was unable to find a font set that looked just right so he set out to make his own TrueType font. He managed to find a sample image of the glyphs that the VT220 used as fonts. Using a collection of free software he sliced the image into 256 different parts, resized and converted to one-bit index images, and converted these to vector graphics. This was accomplished with a bit of python, an image tracing program, and font editor called FontForge.

Take some time to dabble with these font tools. With an adequate sample you should be able to reproduce any font set. We won’t achieve anything as sophisticated as the font printed with bacteria, but this will be a start in the right direction.

[Florian] is proud to announce libTISCH 1.0 is finally ready for release. We told you about libTISCH just under a year ago and how it is a multitouch framework that factors more on the software side of things, instead of hardware for multitouch interfaces. A lot has changed including more widgets, more gestures, more hardware support, and some other nice features. If you’re looking into making your own multitouch surface, or making your own widgets for a multitouch surface – libTISCH would be a great place to start.

[AndyGadget] built a haunted box as part of his Halloween preparations. This follows in the footsteps of the Knock Block we saw earlier this month but makes several hardware changes. He’s replaced the solenoid with a DC motor that rotates an arm to do the knocking. He’s avoided any CNC work by using a softwood box from a craft store as the enclosure. For control circuitry he’s used an 8-pin PICAXE Microcontroller that ‘listens’ for knocking on the box via a piezo buzzer. It will mimic knocks back to you, and if it hears the right combination The Addams Family theme song is played. This useless machine will make a great office conversation piece and with this simplified design it’s much easier to build than the Knock Block. See it perform after the break.