Android Controlled Monitor Stand Uses Marbles As Ball Bearings

July 6, 2012 by 20 Comments

[mobile_earth_explorer] sent in an Instructable he put together documenting an Android-controlled rotating monitor stand he built.

The stand itself is three disks turned on a lathe out of a 18mm thick board. After turning these disks, [mobile_earth_explorer] hopped over to his bench grinder and made a semicircular tool to carve out the track for the ball bearings.

Once the disks could rotate freely on each other, the only thing left was to carve out a space for the servo, Arduino, a pair of pots, and the wiring. The pots control the maximum speed of the monitor stand as well as provide a manual rotation control for when your phone is across the room.

[mobile_earth_explorer] wrote the Android app so up to five of these swiveling monitors can be controlled by just one Arduino; yes, that might be overkill for home or office use, but we’re sure it would be highly useful for some sort of presentation.

You can check out a few videos going over the conception and construction of [mobile_earth_explorer]’s monitor stands after the break.

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Taking A Moon Light From Grayscale To Full Color

July 6, 2012 by 6 Comments

[Terry Miller] picked up a moon light on the cheap. All it does is light up some white LEDs to simulate moon phases after sensing nightfall via an LDR. He figured he could do better and set out to replace the electronics with a more colorful offering.

He chose to use an ATmega328 because he already had it on hand. The chip drives a series of RGB LEDs in a multiplex arrangement. To protect the I/O pins (and drive the LEDs at their target current) he is using a set of high and low side MOSFETs. Rather than rely on the light sensor to switch on the lamp he decided to add an IR receiver. In the video after the break you can see that this lets him cycle through colors and effects, in addition to switching the lamp on and off with a remote control.

With the enclosure put back together he is still able to reprogram the chip thanks to a serial header included in the design. The device is battery operated and the life estimates are included in his write-up.

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CNC Zen Gardening

July 6, 2012 by 9 Comments

The Harford Hackerspace in Baltimore, Maryland just went public with the zen garden they built for the Red Bull Creation contest. It’s a CNC creation that will help ease your frustration with that DIY 3d printer that you just can’t seem to get calibrated correctly.

On the hardware side the base of the machine serves as a sandbox. Finding the correct grain size of the medium was one of the more difficult parts of the build. The stylus is driven along three axes using a gantry common in CNC builds. The pulleys and some brackets were 3d printed, with the remained of the brackets being laser cut from wood. The Bullduino commands the stylus via a stepper motor control board, and drives the LEDs via a bank of MOSFETs. Limiting switches were also included to ensure an error didn’t result in damage to the device.

After the break you can see a build montage put to one of the greatest 8-bit game soundtracks of all time. The one thing we wish they would have shown is the built-in leveling bar that is responsible for “erasing” the garden.

Update: The Harford Hackerspace members came through with a new video that shows the ‘erasing’ process. You’ll find it after the break.

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Ancient Radio Repair

July 6, 2012 by 39 Comments

They sure don’t build them like that anymore. [J.W. Koebel] managed to take this 1934 Simplex Model P radio and bring it back to life.

So where do you start with a repair job like this one? Being a ham radio guy he has a good idea of what he’s doing, and started by replacing the AC capacitor with one which will provide quality noise filtering. He tried to make fixes throughout that would improve functionality and declutter the wire mess. This led him to find a snapped solder connection on the volume knob. Next he tested out the speaker and found that the primary transformer needed replacing. After as replacing the A67 converter (we’ve got no idea what that is) he swapped out the rest of the original capacitors, most of the resistors, and fixed the mechanical problems with the tuning dial. The result is a working radio that looks fantastic!

[via Reddit]

Acrylic RPi Case You Can Make Without A CNC Machine

July 6, 2012 by 15 Comments

[Simon Inns] is showing off the Raspberry Pi case which he built out of acrylic. It provides a lot more protection than a flimsy film case, but it is also a little bit more involved to fabricate. No, this doesn’t need to be laser cut, but to get the nice edges [Simon] used a band saw which many don’t already have in their shop. Ask around, or poke your head in at the local Hackerspace. It only takes a few minutes to cut out the parts.

It sounds like either 8mm or 6mm acrylic will work for this project. Aluminum pipe serves as a spacer to keep the two main sheets in place. The RPi board itself is held in position by a few well-place acrylic chunks super glued in place. You can see the entire build process, including rounding cut edges with a torch, in his video embedded after the break.

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Book Review: Eight Amazing Engineering Stories

July 6, 2012 by 8 Comments

We’re big fans of [Bill Hammack], aka the Engineer Guy. His series of engineering videos dredge up pleasant memories of watching Mr. Wizard but spin to the adult science enthusiast. The most resent season (he calls it series #4) scratches the surface of the topics covered in his book Eight Amazing Engineering Stories, which was written with fellow authors [Patrick Ryan] and [Nick Ziech]. They provided us with a complimentary digital copy of the book to use for this review.

The conversational style found in the videos translates perfectly to the book, but as with comparing a novel to a movie, the written word allows for much more depth. For instance, we loved learning about how Apple uses anodization to dye the aluminum used for iPod cases. The same presentation style makes the topic easily understandable for anyone who took some chemistry and math in High School. But primers a sidebars offer an optional trip through the looking-glass, explaining the history behind the process, how it compares to natural materials, and what trade-offs are made in choosing this process.

Some of the other topics included are how CCD camera sensors, lead-acid batteries, mems accelerometers, and atomic clocks work. As the book progresses through all eight topics general concepts the complexity of the items being explained advances quickly. By the seventh story — which covers the magentron in a microwave oven — we’d bet the concepts challenge most readers’ cognition. But we still enjoyed every page. The book would make a great pool-side read. It would make a great graduation gift (too bad we missed that time of year) but keep it in mind for any science minded friends or relatives. You can see [Bill’s] own description of the book and all its formats in the clip after the break.

TLDR: Buy it or give it as a gift

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Turning A Bunch Of Solenoids Into A Performance Of Stomp

July 6, 2012 by 3 Comments

Say you have a handful of solenoids, a copy of MaxMSP, an Arduino, and access to a whole bunch of parts in a textile museum. What do you do? If you’re like [Luke], you’ll probably come up with an Arduinofied performance of Stomp, played on dozens of old gears, light fixtures, and various other metal parts.

To control what noise sounds when, [Luke] used a Touch OSC interface running on an iPad to send MIDI information to Ableton. From there, MAX/MSP sends messages to an Arduino to actuate the solenoids on cue. The interface is set up so anyone can make their own compositions by reusing patterns into loops of solenoids making noise. Sure, it’s not the dulcet tones you would expect from a more traditional instrument, but [Luke] manages to put on a good show.

While [Luke]’s instrument may sound overly mechanical and dissonant, it’s entirely possible to replace the objects he’s hitting with the solenoids with something a little more melodious. Putting a few solenoids in a cave wouldn’t be a bad idea; too bad it’s already been done.