Breadboarding a 4-bit ALU

[TGTTGIT] recently took the plunge and decided to build his own computer using logic chips. He just completed a 4-bit ALU which can compute 18 functions. It took a long time to get the wiring right, but in true geek fashion his build was accompanied by an alternating Chapelle’s Show and Star Trek: TNG marathon playing in the background.

This project is the stepping stone for a larger 16-bit version. The experience of wiring up just this much of it has convinced him that an FPGA is the only way to go for the future of the build. But since he had already ordered the chips it was decided that the only thing to do was to see this much through. He used the truth table from The Elements of Computing Systems for the design and posted several times about the project before arriving at this stopping point so you may be interested in clicking through the other post on his blog. There’s also a lot of other TTL computer projects around here worth checking into.

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Adding a sound synthesizer to a ‘don’t-touch-the-sides’ maze game

Part of the fun of the classic game of Operation is the jump you get from the loud buzzer which sounds if you touch the sides. This exhibit piece uses the same principle of lining the edges of a track with metal, but instead of an annoying buzz, each touch will issue a bit of music. That’s because the maze has been paired with a synthesizer. Instead of one sound wherever the stylus touches the sides, different parts of the maze act as one of 94 keys for the synthesizer.

There’s a lot more built into the base of the device than just a maze game. The knobs are used to alter the audio effects and the buttons work in conjunction with they stylus to sequence audio samples. There’s even a graphic LCD screen which shows the currently playing wave form. You can get a better look at the project in the video after the break.

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2708 EPROM dumper

[Andrea “Mancausoft” Milazzo] has been restoring old equipment which often contain EPROM chips. He thought he was all set with an EPROM reader which easily dumped the data from 2716 chips and a few others. But he found that the hardware was unable to read 2708 and 2704 chips. His solution was to build a PIC-based EPROM dumper.

You may remember from some of our recent features that these chips are something of a ticking clock. They store program code and other information vital to the functioning of old hardware. Since they’re erased with UV light, years of exposure to ambient light can zap some of the data.

The specs needed to read a chip of this type are rather rudimentary. There are ten address pins and eight data pins. [Andrea] also needed a way to get data from the microcontroller to a computer for backup. He uses two more pins for this purpose, bringing the I/O count to 20. He went with  PIC 18F4610 and built the rest of the reader around it.

Mind-controlling cockroaches

Producing micro robotics is not yet easy or cost-effective, but why do we need to when we can just control the minds of cockroaches? A team or researchers from North Carolina State University is calling this augmented Madagascar Hissing cockroach an Insect Biobot in their latest research paper (PDF). It’s not the first time the subject has come up. There have already been proofs in research and even more amateur endeavors. But the accuracy and control seen in the video after the break is beyond compare.

The roach is being controlled to perfectly follow a line on the floor. One of the things that makes this iteration work so well is that the microcontroller includes a new type of ADC-based feedback loop for the stimulation of the insect brain. This helps to ensure that the roach will not grow accustom to the stimulation and stop responding to it. Since this variety of insect can live for about two years, this breakthrough makes it into a reusable tool. We’re not sure what that tool will be used for, but perhaps the next plague of insects will be controlled by man, and not mother nature.

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Rickrolling remote control prank

This device is a prank or gag that [Eric Heisler] came up with. It will intercept IR remote control codes and play them back after a bit of a delay. The example he shows in the video (embedded after the break) catches the television power signal from a remote, then sends it again after about thirty seconds. This shuts off the TV and would be extremely annoying if you were unable to find the device. Fortunately (for the victim), [Eric] included a piezo buzzer that Rickrolls after sending each code. Just follow that tune to find the offending hardware.

He chose to use an ATtiny10 microcontroller. It looks like it’s realizing its full potential as the six-pin package use all available I/O to control the IR receiver module, an IR led, and the buzzer. It runs from a coin cell without regulation and the circuit was free-formed on a tiny surface mount breakout board which hosts the microprocessor.

Kalman filter keeps your bot balanced

If you’re looking to improve the stability of your self balancing robot you might use a simple horrifying equation like this one. It’s part of the journey [Lauszus] took when developing a sensor filtering algorithm for his balancing robot. He’s not breaking ground on new mathematical ideas, but trying to make it a bit easier for the next guy to use a Kalman filter. It’s one method of suppressing noise and averaging data from the sensors commonly used in robotic applications.

His robot uses a gyroscope and accelerometer to keep itself upright on just two wheels. The combination of these sensors presents an interesting problem in that accelerometer input is most accurate when sampled over longer periods, and a gyroscope is the opposite. This filter takes those quirks into account, while also factoring out sensor noise. Despite the daunting diagram above, [Lauszus] did a pretty go job of breaking down the larger function and showing us where to get the data and how to use it in microcontroller code.

humanoid Robot Kinects with its enviroment

[Malte Ahlers] from Germany, After having completed a PhD in neurobiology, decided to build a human sized humanoid robot torso. [Malte] has an interest in robotics and wanted to  show case some of his skills.The project is still in its early development but as you will see in the video he has achieved a nice build so far.

A1 consists of a Human sized torso with two arms, each with five (or six, including the gripper) axes of rotation, which have been based on the robolink joints from German company igus.de. The joints are tendon driven by stepper motors with a planetary gear head attached. Using an experimental controller which he has built, [Malte] can monitor the position of the axis by monitoring the encoders embedded in the joints.

The A1 torso features a head with two degrees of freedom, which is equipped with a Microsoft Kinect sensor and two Logitech QuickCam Pro 9000 cameras. With this functionality the head can spatially ”see” and ”hear”. The head also has speakers for voice output, which can be accompanied by an animated gesture on the LCD screen lip movements for example. The hands feature a simple gripping tool based on FESTO FinGripper finger to allow the picking up of misc items.