2708 EPROM Dumper

September 10, 2012 by Mike Szczys 4 Comments

[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

September 10, 2012 by Mike Szczys 81 Comments

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

September 10, 2012 by Mike Szczys 18 Comments

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

September 10, 2012 by Mike Szczys 19 Comments

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.

A Fifty-dollar Projection Screen You Can Be Proud Of

September 8, 2012 by Mike Szczys 31 Comments

[Lou] wrote in to share the fifty-dollar projection screen he built in his home. We’ve seen several of these projects lately. Unlike the one used at a lake cabin, or the other that fills an awkward alcove, this version doesn’t use fabric for the screen. He actually painted it right on the wall.

The key to achieving a great end product is to make sure your wall is flat. [Lou’s] instructional video (embedded after the break) shows how to patch holes in the wall, and repair high spots. Before beginning the process he uses his projector’s grid feature to map out the portion of the wall that will be used as a viewing area (that’s the grid seen on the screen above). Once the area has been marked with masking tape and carefully repaired he paints it with bright white or silver paint. You might also consider a paint additive for better results. We’ve seen sand blasting beads used for this purpose.

A frame is added to the area to make it look like a proper screen. This is nothing more than molding covered in black fabric. [Lou] stretches the fabric around the molding, using duct tape to hold it in place until it can be stapled down.

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Beautifully Crafted Geiger Counter A Must If You Live In A Hot Zone

September 8, 2012 by Mike Szczys 10 Comments

Have a little class when you’re screening for radioactive particles. You can follow the example which [Moustachenator] has set with this gorgeous Geiger counter case.

The business end includes the same Geiger tube we see in all of these projects, but he took the time to solder together a tidy circuit board and housed it in an acrylic tube. it connects to the base unit using a springy telephone handset cord. The laser cut walnut enclosure offers plenty of room for the ATX power supply hidden inside. This feeds the Arduino which runs the system, and provides a powerful source for the Nixie tubes which serve as the display. The attention to detail when it came time to assemble the case is what lends an antique look to the project, even though everything was built from the ground up. Check out the video after the break to see a brief demonstration.

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Rotary And Cordless Phones Mashup

September 7, 2012 by Mike Szczys 5 Comments

This pile of hardware marries telecommunications hardware from distinctly different generations. [Andrew D. Farquharson] wanted the retro look and operation of a rotary phone, with the convenience of a modern cordless. He combined the two technologies to achieve his goal.

The first problem was to find a way to translate the rotary inputs to something he could use. There are already a bunch of projects that use rotary hardware so he didn’t have to reinvent the wheel. He followed this guide to connecting Arduino to a rotary phone.

The next step was to interface with his cordless phone. He ditched the case and soldered rainbow ribbon cable to the entire button matrix. An opto-isolator is used to protect the Arduino while making each connection. Finally, he patched into the mechanism which monitors the cradle to see if the handset has been picked up. It sounds like his code lets you enter the number on the dial, then pick up the handset to actual transmit it through the cordless phone.