Moppy lets you play your floppy drives

Get ready to join a band. Just follow the guide over at the Moppy project page and you’ll have your very own floppy drive instrument.

The name is a mashup between Musical and Floppy. By using an Arduino UNO as a translator, you can command an array of floppy drives with a musical keyboard (think piano). The head on each floppy drive is controlled by a stepper motor which will put out some sweet sounds if driven at just the right frequency. The lower notes tend to fair a bit better than the high range. One great example of this is the Imperial March theme as heard after the break.

Once you get the base system up and running, it’s time to think of some alternate interfaces. Sure, you can obvious things like toy keyboards. But wouldn’t it be more fun to make it fruit controlled?

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Pleasing results from a CNC mill project

[Roy] is getting to the end of his second CNC mill project and finally seeing some results. Here you can see a bear he milled in some floural foam.

The project started out as an Arduino-based pen plotter. It move the pen along one axis, and the drawing surface along another, with the third axis allowing the pen to be lifted and repositioned. With that in his back pocket he went all out and began what he calls the Mark II. He used T-slot aluminum for the frame, which really helped when it came to aligning the linear rod supports for each axis. After a lot of drilling, and tapping he managed to bring each axis on line one at a time. A pre-fab CNC driver kit drives the stepper motors, making them groan as they do their work. hear it for yourself in the test video after the break were the machine is first tested as a pen plotter.

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Quieting a pendulum clock every night

[Vinnie] has a wonderful old clock from his grandmother; it’s an exquisite antique with a real mechanical movement and a charming set of bells that ring every hour. Unfortunately, those chimes are a bit of a disturbance to neighbors at 2 o’clock in the morning. Previously, [Vinnie] had been stopping the clock every evening, and hoped he would remember to start the pendulum in motion 12 hours later. This was a chore, so he decided to automate the process.

The build is simple and clever; a small stepper motor is mounted in the clock just underneath the pendulum. Every 12 hours, the stepper motor moves a lever and slowly stops the pendulum over the course of a dozen or so seconds, silencing the clock movement. Twelve hours later, the motor turns again setting the pendulum in motion.

The parts count for this build is very low – basically just an ATmega88, a Darlington array to drive the stepper, and a 32.768kHz crystal. We can think of a few friends and relatives with loud clocks in their house, so we might have to build a few of these to give away.

Take a look at the demo video after the break to see how [Vinnie] stops his grandmother’s clock every night.

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Giant pencil used as an Etch a Sketch stylus

The gang over at Waterloo Labs decided to add a team-building aspect to a plain old Etch a Sketch. Instead of just twisting the two knobs with your own mitts, they’re converting this giant pencil’s movements into Etch a Sketch art.

The challenge here is figuring out a reliable way to track the tip of the pencil as it moves through the air. You may have already guess that they are using a Microsoft Kinect depth camera for this task. The Windows SDK for the device actually has a wrapper that helps it to play nicely with LabView, where the data is converted to position commands for the display.

On the Etch a Sketch side of things they’ve chosen the time-tested technique of adding gears and stepper motors to each of the toy’s knobs. As you can see from the video after the break, the results are mixed. We’d say from the CNC ‘W’ demo that is shown there’s room for improvement when it comes to the motor driver. We can’t really tell if the Kinect data translation is working as intended or not. But we say load it up and bring to a conference. We’re sure it’ll attract a lot of attention just like this giant version did.

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[Pythagoras], a Delta Robot for Drawing

[Pythagoras] is a delta robot built originally using RC servos. Humbly, [Aaron] “concedes” that the first version of his delta robot using hobby servos was easy to build. As anyone who has built any kind of robot knows though, there is definitely a lot of work involved in even the simplest robot. Coordinating three axes and programming it to draw a picture is a really great accomplishment.

The second version, however is currently in development and uses stepper motors instead of servos. These upgraded motors should make the robot faster, more controllable, and more accurate. This version is at least somewhat working as evidenced by the time-lapse video after the break.

Although the title page listed above is a little sparse on build details, if you dig deeper into the page, there are actually 15 articles about the ‘bot, so be sure to poke around. [Read more...]

Reduced-cost Braille display for use with computers

Apparently a Braille computer display can cost several thousand dollars. That’s why [David Pankhurst] is working on a low-cost alternative. His offering is an open source version he calls the Audrey Braille Display.

The concept is quite good. This prototype has one line of six Braille characters. Each character is made of two sliding strips containing eight arrangements of bumps. These can make up any character when positioned correctly. Two motors do all the work, one engages a single strip to reposition it, the other moves the first motor to select which strip should move. This is explained quite well in [David's] most recent post. Or you can get a preview of the physical build here.

The concept is sound, but the refresh rate must be very slow. We wonder if there’s a way to keep one motor stationary and use solenoids to engage a drive shaft on the individual slide rods? This way, every row could be changed at the same time, disengaging when the appropriate slot is reached.

This hardware is much needed until developing Braille technologies actually come to market.

[via Dangerous Prototypes]

Full featured security lock demonstration

[Arshad Pathan] let us know about his latest project, a modular code lock that can be adapted to many different situations.

The user interface is made up of a character LCD screen and a 3×4 keypad. For this example [Arshad] is using a stepper motor as the locking mechanism. When the board is first powered up it runs the stepper in one direction until receiving input from a limiting switch. In this way, the microcontroller calibrates itself to ensure the lock is in a known position. From there it waits for user input. An unlocked door can be locked at any time by pressing the * key. Unlocking requires entry of the correct password. And a password can be changed by entering 9999 (followed by the old password when prompted).

In the video after the break [Arshad] does a great job of demonstrating the various modes which he has programmed. This stands on its own, but we always love to have more details so we’ve asked if [Arshad] is willing to share a schematic and the source code. We’ll update this post if we hear back from him.

Update: [Arshad] sent in a couple of schematics which can be found after the break.

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