Hackaday Links: May 25, 2014

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[Matt] wanted his own light saber. You could argue that this is nearly as dangerous since you can’t see the beam and it doesn’t end a few feet past the business end of the grip. Plus there’s that who “not actually a Jedi” thing.

We don’t know if retro computing fans are going to love or hate this (translated). On the one hand it’s pretty cool to see a ZX81 clone up and running. On the other hand, an Amiga 600 case was sacrificed to serve as the body for the hack. [Thanks Juan]

Watchdog timer. If you know what that is your mind immediately says “good idea” when you hear the word. If you don’t know, you need to learn. Watchdogs are reset timers that are built into most microcontrollers. If your firmware gets stuck and doesn’t maintain the timer’s counter at a regular interval the watchdog it will perform a hardware reset and hopefully your hardware will start functioning again. Here’s a guide for using the watchdog in an Arduino, but the concepts are pretty much universal.

We see all kinds of stepper-motor based music machines. One of our favorites was this recent floppy drive jukebox. But not every song is going to sound good on this type of hardware. One that does sound especially neat is the Doctor Who theme on an array of 8 drives.

And finally, if you’re struggling with surface mount soldering we recommend grabbing two soldering irons. But in a pinch just grab some heavy gauge copper wire and wrap it around your soldering iron tip. It ends up being a two-point soldering iron set for the size of specific components such as 0805 resistors. [Thanks Rupert]

Fail of the Week: CPLDs That Release Blue Smoke

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The card you see above is a floppy drive emulator for Macintosh. [Steve Chamberlain] has been hand assembling these and selling them in small runs, but is troubled by about a 4% burn-out rate for the CPLD which has the red ‘X’ on it. He settled into figure out what exactly is leading to this and it’s a real head-scratcher.

He does a very good job of trouble-shooting, starting with a list of all the possible things he thinks could be causing this: defective part, bad PCB, bad uC firmware, damage during assembly, solder short, tolerance issues, over-voltage on the DB connector, or bad VHDL design. He methodically eliminates these, first by swapping out the part and observing the exact same failure (pretty much eliminates assembly, solder short, etc.), then by measuring and scoping around the card.

The fascinating read doesn’t stop with the article. Make sure you work your way through the comments thread. [Steve] thinks he’s eliminated the idea of bad microcontroller code causing damage. He considers putting in-line resistors on the DB connector but we wonder if clamping diodes wouldn’t be a better choice (at least for testing purposes)? This begs the question, why is he observing a higher voltage on those I/O lines during power-up? As always, we want to hear your constructive comments below.


2013-09-05-Hackaday-Fail-tips-tileFail of the Week is a Hackaday column which runs every Wednesday. Help keep the fun rolling by writing about your past failures and sending us a link to the story — or sending in links to fail write ups you find in your Internet travels.

The Most Beautiful Floppy Disk Jukebox Ever

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Playing music on floppy drives is something that has been done to death. [kiu]‘s RumbleRail is something else entirely. Yes, it’s still a collection of floppy drives playing MIDI files, but the engineering and build quality that went into this build puts it in a class by itself.

Instead of the usual assemblage of wires, power cords, and circuits that accompany most musical floppy drive builds, [kiu]‘s is an exercise in precision and modularity. Each of the eight floppy drives are connected to its own driver with an ATMega16 microcontroller on board. The microcontrollers in these driver boards receive orders from the command board over an I2C bus. Since everything on the RumbleRail is modular, and the fact [kiu] is using DIP switches to set the I2C address of each board, this build could theoretically be expanded to 127 voices, or 127 individual floppy drives each playing their part of a MIDI file.

The RumbleRail can also operate in a standalone mode without the need for a separate computer feeding it data. MIDI files can be loaded off an SD card by the main controller board, and decode them for the floppy drivers.

If you’d like to build your own RumbleRail, all the board files, schematics, and firmware are up on [kiu]‘s git. There are, of course, a few videos below of the floppy jukebox in action.

[Read more...]

Hackaday Links: Sunday, April 21st, 2013

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Regular reader and master hacker [Bill Porter] got married. Congratulations [Bill] and [Mara]! The two of them just couldn’t leave their soldering irons at home. The actually swore their vows by soldering together a circuit during the ceremony (blinky wedding dress, el wire tuxedo, and all).

[Kevin] sent in a link to [Red Fathom's] hacked Wacom tablet. It’s the screen from a Wacom-enabled laptop brought back to life with a Teensy and an LVDS interface module.

The Neato XV-11 is able to find its charging station when the batteries run low. [Derek] figured out that you can make a second station using some reflective tape.

If you use your drill a lot you’ll eventually break the rubber thing that holds the key to the chuck. Here’s a way to 3D print a replacement.

[Torxe] put eight floppy drives to use as a polyphonic Arduino-controlled MIDI player. And while we’re on the subject of Arduino controlled projects you should take a look at this web-interface to tell you if the foosball table is being used.

And finally [Th3 Bad Wolf] sent in this link to a milling machine built out of LEGO. It is able to mill floral foam and uses a lathe-like setup for one of the table axes.

Building a six-channel floppy drive synth from start to finish

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We’ve seen scores of floppy drives play music, but never before have we seen a project as clean as [Rupert]‘s Moppyduino. It’s an Arduino-based board that controls the stepper motors in six separate floppy drives, coaxing them in to playing music from a MIDI file.

The Moppyduino is more than just a convenient way to control the stepper motors in six floppy drives. It’s also a great example of what can be done with home PCB fabrication; the entire project was designed and constructed in [Rupert]‘s workshop.

After designing the circuit, [Rupert] printed it out on a laser printer onto a plastic transparency sheet. This was transferred over to a copper clad board, etched, and drilled. After assembly, [Rupert] attached a USB FTDI controller to receive data converted from MIDI data with a Java app.

The end result – housed in a custom Corian enclosure – is one of the best looking floppy drive synths we’ve ever seen. You can check out the process of building this awesome instrument after the break.

[Read more...]

A Floppy Drive Orchestra

With 8 drives working in concert, this “floppy drive array orchestra” takes drive music to a whole new level!  As if that wasn’t enough, [SileNT] decided to use the16x64 LED array that he’s been working on in concert with the drives.

For those that remember, we’ve actually featured [SileNT], AKA [Pawel]‘s, work before, where we were impressed that he was able to play the Imperial March from Star Wars on 2 floppy drives. He’s planning more information about his floppy drive music making in the future and maybe even instructions on building your own personal disk drive orchestra. Apparently [SileNT] has an abundant supply of 3 1/2 inch drives, so maybe even this feat can be topped…

Be sure to check out the video after the break of these 8 drives in action. In the video, more tunes are promised “soon”, so be sure to check back or subscribe to him on Youtube for more sweet melodies. [Read more...]

Star Wars Imperial March Played by Dual Floppy Drives

Although many have made some sort of music with improvised electronics, few sound as cool as this Imperial March from Star Wars played by two floppy drives. According to [Pawel], “It’s nothing new” and quite simple. This may be true as we’ve featured an Imperial March-playing floppy drive here before, but it was only one drive. Although it may not be the London Symphony Orchestra, the two drives together sound quite good!

According to him, the FDD has a fairly simple interface. To move the head, one simply needs to pull the DRVSB pin low and then activate the STEP pin on a falling edge.  This will make the head move one direction dependent on the DIR pin state. In this case, an ATMega microcontroller is moving everything. An explanation of the pins used in this hack can be found here.

Although it may look like an intimidating hack on the surface, something like this might be a neat project to try with some old hardware and an Arduino or other controller! [Pawel] did have the idea to hook up a 5 1/4″ and 8″ drive to make a full FDD orchestra, so we can’t wait to see what he comes up with! [Read more...]

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