Melloman Tape-looping Keyboard

[Michael] tipped us off about an incredible build from back in 2005. The Melloman is a keyboard that uses a different tape loop for each key. The instrument is generally known as a Mellotron, and consists of a different looping tape for each key. When a key is depressed, the head comes into contact with the key and plays the sound sample.

This particular implementation uses 14 Walkmans to supply the tape loops. The Walkman units are constantly playing but the audio output is not enabled until a key is depressed. The main description of the instrument is on the final project page linked above but there are many construction photos available in the build log.

Update: After the break we’ve embedded a video that will take you on a tour of the components of the Melloman. To clear up the looping issue: a Mellotron uses tape loops, but the Melloman uses tapes that are 30 minutes on each side instead of loops.

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Crushtoberfest – Can You Pwn Tom Selleck?

[flickr video=http://www.flickr.com/photos/jmillerid/4055251585/]

On rare occasion, the celestial bodies that control engineering and design awesomeness move into alignment and cast their blessed star dust upon a hacker. Today, we can witness the glorious outcome of such an alignment. Although almost unheard of, it’s a good omen that such a blessed hacker also be adorned with a wickedly furry face.

[Joel] wanted to up the ante for a yearly work gathering. He set out with the concept of Crushtoberfest, a test-your-strength game where a stake is hit with a mallet and the resulting force rings a bell. But bell ringing is for normal projects, [Joel’s] muse required LEDs and fire as a reward for success. In fact, Tom Selleck (god of all things mustache) becomes angry at successful contestants to the point that his eyes will flash red and flames shoot out of his ears.

The mechanical input is a clever design. The stake used as the target is a 6×6 block with some old tire tread affixed to the top of them. The stake rests on a piece of radiator hose that is sealed on one end and connected to a pressure sensor on the other. Radiator hose is resilient, so it takes quite a blow to cause much compression, which is then translated into a value by an Arduino via the pressure sensor. [Joel’s] gone to the effort of building gravitational deceleration into the progress tracker of the vertical string of LEDS. Too bad he didn’t have access to an addressable LED rope to make this easier, but he did pull it off nicely. He also goes into detail about prototyping and building some fireball modules.

Go now and read his blog (oldest at the top, newest at the bottom). We can call the experience nothing short of delightful.

Ask Hack A Day: Touch Screen Hack

Reader [Chad Essley] asked us:

“I’m wondering if the vast knowledge base of HackADay’ers out there might know of some way to turn almost any laptop into a touch screen of some kind. Actually, any surface.”

He has an older Wacom Tablet, and would like to be able to add resistive touch screen capabilities so that he isn’t forced to use the Wacom pen. Being an artist and part time hacker, he even summed up the question in a comic-style post.

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IPv6 To 1-wire Protocol Translator

[Fli] assembled an AVR based system that can assign IPv6 addresses to 1-wire components. An AVR ATmega644 microcontroller is used in conjunction with an ENC28J60 ethernet controller chip. To get up and running with IPv6 on this meek hardware [Fli] ported the uIPv6 stack from the contiki project over to the AVR framework. Although he encountered some hardware snafus along the way, in the end he managed to get five sensors connected to the device, each with their own IP assigned using the stack’s alias capability.

This is great if you’re looking for a low-cost IPv6 solution. We’re not sure if there’s much demand for that, but it’s useful for that 1-wire home automation setup you’re considering.

McLVDT: A Straw-based Sensor

We saw [Kevin’s] home-built Linear Variable Differential Transformer in a YouTube video last week and wanted to know more. We’re in luck, he agreed to share all the details as well as a bunch of information on these sensors. An LVDT is used to measure distance along a straight path. Unlike a linear optical encoder, this method uses measurements of inductance between two electrical coils to judge the distance.

[Kevin] used some magnet wire wrapped around two straws of different diameter to fabricate his sensor. A signal generator is connected to the primary coil and the resulting signal induced in the secondary coil is measured to reveal the change in physical position. Check out the video after the break to see the results.

It’s not hard to get your hands on a McDonald’s straw (hence the name ‘Mc’LVDT), a smaller inner straw, and a few feet of magnet wire. This will be a fun one to try when those dark winter days start to get to you.

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Minimalistic Circuit Design

[David Terrill], whose exploits we have covered before, has shared with us his techniques for building circuits without a prototype or bread board. [David] managed to incorporate a Dual D flip-flop at the heart of the circuit, as well as an impressive number of transistors, diodes, and other passive components. Unfortunately, the circuit diagram is a little low resolution to really make out the real function, but based on the components, our best guess is a two-output blinking circuit. Maybe for an encore, someone out there will build a circuit built entirely around a battery so that it can be a self-contained system.

Let us know if you have a better copy of this schematic, or a guess at what the circuit does!

DS Goes Full Size – Pockets Everywhere Rally In Protest

It’s hard to believe we missed this one from a couple of years back but we’re thankful that reader [Christian] tipped us off about it. This a Nintendo DS with two tablet pc screens being used as an external display. He’s using an FPGA but not to emulate the processor. It is translating the video data from the DS board into usable signal for the larger LCD screens. In the video after the break you can see that pen input has been implemented, with the FPGA sending location data back to the DS.

[Neal], the creator, priced the project out at around $580. It’s worth a lot more considering the know-how needed to get the video scaling and pen input right using the FPGA. It won’t fit in your pocket, but it doesn’t have a case either so it’s not going anywhere anytime soon.

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