Mechanical Turing Machine Can Compute Anything…slowly

March 25, 2011 by Mike Nathan 12 Comments

mechanical_turing_machine

For several years, [Jim] has wanted to construct a fully-mechanical universal Turing machine. Without the help of any electronic circuits or electrical input, his goal was to build the machine using simple hand tools and scrap materials.

If you are not familiar with the concept of a Turing machine, they are devices that manipulate symbols or input from a strip of tape, according to a set table of rules. By definition, a Turing machine should be adaptable to simulate the logic of any computer algorithm, albeit in a much slower fashion than you would see from a computer.

He has replaced the strip of tape with a wire grid, and the symbols have been implemented in the form of ball bearings placed on the aforementioned grid. His hand-cranked machine uses magnets to lift the input symbols from the grid, processing them according to the rules table he routed out of a wood block.

The implementation is definitely clever, though [Jim] admits it is not without its problems. He took it to Maker Faire UK, and most people didn’t quite understand what they were seeing without a full explanation. The machine is not quite as reliable as he would like it to be, and he would like to make it a bit more powerful as it currently would take months to add two numbers together.

Keep reading to see a brief video demo of his Turing machine in action, and check out his blog if you want to see more information on how the machine was built.

Interested in seeing more Turing machines? Check out these two machines we featured a while back.

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CD Phonograph Brings Old-time Charm To Modern Music

March 13, 2011 by Mike Nathan 23 Comments

phonograph

[Jozerworx] had always wanted to build a CD player that looked like an old-time Victrola Phonograph player, though he never seemed to be able to find the time to do it. With all of his other projects out of the way, he decided to finally get started on building his phonograph.

He went garage sale hunting and found the perfect base for his project – an old wooden box adorned with tarnished brass hardware. He started in on the project immediately, dismantling a cheap CD player and mounting the motor/laser assembly on the top of the box. The CD player internals were installed inside the wooden box, along with a small audio amplifier stripped from a portable iPod speaker.

A brass horn was fashioned out of an ornament, in order to complete the phonograph feel, but also to act as a passive amplifier. He then mounted a series of switches on the top of the box to allow him to control the CD player’s basic functions.

[Jozerworx] says that it sounds decent, though there are some things he would change. He plans on switching out the audio amplifier and possibly the speakers at some point in the future. He is also still keeping his eye out for a larger, and more effective horn.

A 555 Synthesizer

March 9, 2011 by Kevin Dady 12 Comments

Inspired by the memory of a childhood electronics kit, [Frank] decided to make a new 555 Synthesizer and enter it into the 555 contest. [Frank’s] remake is played with a stylus, and sports an attack and release envelope circuit, housed in a quick but effective acrylic case.

Using a single 555 timer, a hand full of capacitors, two transistors, and a healthy dose of resistors and potentiometers, the sound is quite impressive thanks to optional filtering, enveloping, and a lot of fine tuning. Full schematics, bill of materials, formulas, and board files are all available along with sources for some of the more specialized potentiometers.

Join us after the break for a ~13 minute long video, which is pretty cool, as it shows the device from prototype, and does some fast forward action though to the final product pictured above, though if you just want a demo of the 555 synth fast forward to 10:44

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DSLR Bellows-mounted Lens Retrofit

March 9, 2011 by Mike Nathan 15 Comments

dslr_lens_retrofit

While digging through a pile of old camera equipment, [Jake] stumbled upon a camera that belonged to his grandfather and was curious to see what sorts of images the old lens would produce. He wasn’t interested in messing around with a film-based camera for his experiments, so he needed to find a way to mount the vintage lens on his newer Canon DSLR.

After considering several options including custom machined adapters and mounting rings built from old Canon lenses, he found a much cheaper solution. He purchased a lens adapter made to mount a particular type of lens to a modern DSLR, and then modified it to fit his lens. It worked perfectly, though he admits the resulting images are not that different than those taken with his regular lens.

Underwhelmed with the images, he decided to mount the lens on a set of bellows he picked up at the local dump. It looks pretty neat, but he has yet to get a chance to take any pictures with his new setup. Hopefully we’ll see some test shots soon.

If anyone has experience with using bellows lenses on a modern DSLR, we’re always up for seeing some sample pictures. In the meantime, check out this other DSLR/bellows hybrid project we featured a short while back.

[via BoingBoing]

Old School LED Light Show

March 1, 2011 by Mike Nathan 20 Comments

programmable_lightshow

Building LED arrays that can display all sorts of different patterns is pretty easy these days. Hook up an Arduino, do some charlieplexing, and off you go. When [Viktor] was younger he didn’t have all those fancy schmancy microcontrollers and circuit simulation software you kids have these days. In fact, last we heard, he had to walk to school uphill both ways – in the snow.

That didn’t stop him from building this gem of a project back in 1987. His LED chaser/light show does not use any microcontrollers at all, rather it relies on an EPROM to store predefined display programs. A series of switches are installed on the front of the flasher, allowing him to easily switch between the programs, and a pot is mounted to the front of the device to control the speed of the LEDs.

His light show is pretty slick, even for a project built over 20 years ago. Sometimes you just can’t beat a good, old-school hack.

Continue reading for a video demonstration of [Viktor’s] programmable light show.

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2-bit Full Adder Using Just Thirty Six 555 Timers

February 28, 2011 by Mike Szczys 12 Comments

This 2-bit adder was a lot of work to build. It uses a total of thirty-six 555 timers and it does have the option of adding or subtracting numbers. It’s a rather unorthodox use of the part, depending more on the chip as an inverter and taking advantage of the fact that there’s an NPN transistor built into it. [cpu86] did use some PNP transistors to give him the ability to turn off some of the 555’s to get everything working correctly.

He explains the use of two’s complement in the subtracting feature but the process is just touched on very quickly. Luckily there’s a huge eagle schematic available with his project writeup so that you can follow along and really grasp how this thing works. We’ve generated a PNG and embedded it after the break for your convenience. You’ll find it just after the two videos of the device in action.

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Analog Robotic Concepts

February 26, 2011 by Mike Szczys 20 Comments

Everyone’s getting on board with the 555 timer projects. But [Tom] didn’t just come up with one project, he shared a slew of ideas related to analog robotics. They’re center around servo motor control. You can see in the video after the break he has a pleasing way of sharing a lot of details while also making an easy to view demonstration video. He’ll put up a schematic for about one second and then move on, saving those that don’t care about the details by not droning on.

The first schematic that flashes by is the main circuit for controlling the servo motor. The rest of the concepts build from this circuit, using light, sound, flex, and other sensors as inputs. For instance, the setup above is using a light sensor. When the ball blocks the light the servo moves that vertical rod hitting it out of the way. When it swings back the process repeats. It’s striking how lifelike the reactions are, reminding us of insect movements. But this is really just the tip of the iceberg as he’s got a lot of future video ideas that we can’t wait to see.

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