Investigating The Generative Properties Of A Stepper Motor

January 23, 2012 by Mike Szczys 40 Comments

You probably know that if you spin a motor (mechanically) it generates electricity on what would normally be the inputs. This can be a problem when you shut off a spinning motor and is the reason that protection diodes are built into motor driver circuits. But [Dino] isn’t interested in driving a motor, he wanted to see what he could do with the electricity generated by spinning a stepper motor.

He built the test rig that you see above for this purpose. In the foreground a 12V DC motor is held in place with an electrical conduit clamp. This connects to the stepper motor being tested using a segment of rubber tube. The DC motor provides a reliable input for his experiments, but could be replaced in the future by a propeller to make it wind powered, or by a water wheel. Check out the video after the break to see what kind of juice [Dino] gets out of it, and how it can be used for powering LEDs, recharging batteries, or driving a motor.

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Whac-A-Banker To Relieve Your Frustration

January 23, 2012 by Brian Benchoff 31 Comments

[Tim Hunkin], builder extraordinaire and host of The Secret Life of Machines is a bit frustrated with the current economic climate and decided to take out his frustrations with a game of Whac-A-Banker.

[Tim]’s version of the classic Whac-A-Mole game uses tiny air cylinders to actuate five banker figurines up and down. The figures were cast with polyurethane and are reportedly holding up well. The cabinet is really interesting. When the game isn’t being played, a really boring front panel is displayed. After inserting a few coins, the panel drops into the machine to show the fun and exciting scoreboard.

If you’re ever around Suffolk, England, you can check out the Whac-A-Banker and a lot of other [Tim Hunkin] creations at the Southwold Pier. Thanks [John] for sending this one in. Yes, we did get The Secret Life of Machines in the states on the Discovery Channel, but it has been replaced with shows about trucking. Here’s an archive of the entire series for your viewing pleasure. Kiss your evening goodbye.

Maximite Harkens Back To The Days Of BASIC

January 23, 2012 by Brian Benchoff 49 Comments

Any self-identified geek that spent some time in the 80s will tell you how they used to type out programs into their ‘microcomputer’ with BASIC. It was a simpler time when a computer’s raison d’etre was simply being a BASIC interpreter. These days are long past us now; you can’t simply turn on a computer and have it load a BASIC prompt anymore. This is where [Geoff]’s Maximite single board computer comes in. It’s a tiny little box that whose only purpose is to play around with BASIC.

[Geoff]’s used a PIC32MX microcontroller with 128k of RAM for the CPU of his Maximite. Unlike an Apple ][ or TRS-80, the Maximite version of BASIC can do floating point arithmetic out of the box. To connect to the outside world, the Maximite has VGA or composite out to display the BASIC interepreter. A PS/2 keyboard port provides the input, and a USB port and SD card can be used to load and save programs from a PC.

The Maximite includes a 20-pin breakout for whatever IO you can imagine. This is duplicated on [Geoff]’s mini Maximite that is designed to be the retro throwback of an Arduino. We though those were called BASIC stamps, but if it gets kids programming, we’ll let it slide.

Computing With The Command Line

January 20, 2012 by Brian Benchoff 40 Comments

Here’s something we thought we would never see: computing with just pipes, /dev/zero, and /dev/null.

As a thought experiment, [Linus] imagined a null byte represented an electron. /dev/zero would have an infinite supply of electrons and /dev/null would make a wonderful positive power supply. With a very short program (named mosfet.c), [Linus] can use Linux pipes to control the flow of electrons between /zero and /null. [Linus] used mosfet.c with a very short shell script to create a NAND gate. From there all bets were off. He ended up creating a D flip-flop, 4-bit adder and a counter.

From a bit of cursory research, Linux has a maximum pipe capacity of 1,048,576 bytes and the maximum number of PIDs is 4,194,304 (correct us if we’re wrong). [Linus] can theoretically build some of the classic CPUs of the 70s and 80s with his pipe logic. An Intel 486 is just out of reach, though. If you give someone a NAND or a NOR they’ll eventually build a computer; we thought we’d never see this, though.

Adding Digital Game Indicators To A Neo Geo Arcade Cabinet

January 19, 2012 by Mike Nathan 14 Comments

neogeo

[George] is a Neo Geo aficionado, and among his collection of paraphernalia, he has a MVS-Mini game console. His mini “Multi Video System” is a 2-slot model, meaning that it can hold two game cartridges at a time, which are indicated by plastic cards inserted in the cabinet’s face plate. Instead of swapping those cards out each time he changed cartridges, he thought it would be far cooler to install digital displays instead.

He scoured just about every retail store he could before finding a handful of small 5” digital picture frames that looked to fit the bill. After some careful cabinet modifications he had them wired up and ready for display. The frames don’t hold a ton of pictures, but they do support the use of SD cards. [George] says that he’ll likely just buy a ton of small SD cards, swapping them out whenever he changes games, though over time that might become as tedious as swapping out the plastic cards.

We would love to see [George] take his new digital display up a level, so be sure to share your ideas in the comments. Perhaps we can persuade him to automate things a bit.

Wii Nunchuck On An 80s Computer

January 16, 2012 by Brian Benchoff 3 Comments

For a computer that debuted in the early 80s the MSX was a very respectable machine. Of course these were the days that superimposing graphics over a video was an amazing feat, but [Danjovic] and [Igor] are still having fun with their boxen. They designed a software interface for the Wii Nunchuck (translation) on their trusty MSX computer.

The plug coming out the back of a standard Wiimote is just a simple I2C bus. Many things can be done with this port from plugging in ancient controllers to controlling robots. [Danjovic] and [Igor] managed to write a routine in Basic that converts the I2C data coming out of the Nunchuck to data the MSX can understand without any modification of the hardware whatsoever.

All the guys needed to plug the Nunchuck into the MSX was a voltage divider and a few pull-up resistors between the computer and controller. They got data from both buttons, the joystick and the accelerometer in the Nunchuck and made a small program to display some sprites on the screen to demonstrate this. Check that out after the break.

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The TIM-8 Is The Smallest 8-bit Relay Computer Ever

January 16, 2012 by Brian Benchoff 20 Comments

Who wouldn’t want to build a computer out of relays? We do, but we’ve got too many projects on our plate already. It looks like [rory] has his priorities in order because his build is one of the most amazing we’ve ever seen.

We’ve seen [Harry Porter]’s amazing relay computer and we’re familiar with [Konrad Zuse]’s WWII era endeavours. Relay computers aren’t exactly uncommon, but [rory] built the TIM-8, that may be the smallest 8-bit relay computer ever. The total relay count in the TIM-8 is 152 compared to [Harry Porter]’s 415 relays. This isn’t a fair comparison because [Harry]’s uses 4-pole relays, while the TIM-8 uses 1-pole relays, making the [rory]’s project 8 times smaller than [Harry]’s.

There are a couple of neat features that makes the TIM-8 really exceptional. Programs for the TIM-8 are written in a text editor on [rory]’s desktop, then compiled and printed onto receipt paper. The TIM-8 has a few phototransistors to read the bands of white and black printed on the paper. [rory] has come a long way from a three bit adder made with relays and light bulbs.

Check out a ton of videos after the break. There’s a few demos of programs running off of receipt tape, calculating the Fibonacci sequence, and playing ‘Mary Had a Little Lamb’ on the relay sound card. Thanks to [J. Peterson] for sending this one in.

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