Using Polycarbonate Filament With A RepRap

September 30, 2011 by Mike Szczys 19 Comments

[Rich] couldn’t find any instances where RepRap owners had used polycarbonate as a 3D printing source material. He’s filled that knowledge gap by running multiple polycarbonate printing tests. Polycarbonate is a plastic that is highly resistant to shattering yet it’s still rather soft. With enough effort it can be bent and stretched, but it’s fairly difficult to break the material.

The test spool of polycarbonate was special ordered for this project. [Rich] sourced 1.6mm filament since 3mm material would have been difficult to spool. It melts at a temperature range of 280-300 degrees Celsius, which he reaches with a hot-end extruder design. The printed material comes out a bit cloudy, which may be due to the heating process itself, or due to extruder reversals (he’s not quite sure what’s causing it). But as you can see above and in the video after the break, it’s certainly a viable printing medium.

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Remote-controlled USB Switch

September 29, 2011 by Brian Benchoff 10 Comments

When [beerninja] wanted to swap his USB keyboard from one game console to another without mucking about with wires, he asked the Hack A Day forums for some help. [Meseta] (AKA [UAirLtd]) came to the rescue and built [beerninja] a remote-controlled USB switch.

After opening up a no-name USB switch, [Meseta] discovered that the switching is done with simple relays and switches. A hugely overpowered Forebrain ARM dev board was used to pull each switch low for a few hundred milliseconds to switch the output USB port.

For the infrared remote control, [Meseta] dug into Lady Ada’s IR sensor tutorial and decoded buttons 1 through 4 on a Sky TV remote. Each button from one to four corresponds to the buttons on the USB sharing switch. The ‘0’ button was also decoded as a convenience to put the Forebrain into its reprogramming mode. After drilling a small hole for the IR receiver, the finished project was stuffed back into the original steel enclosure.

Check out the video of the switch in action after the break.

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Battery-less Electronic Dice For All Your D&D Needs

September 29, 2011 by Mike Nathan 42 Comments

electronic_20_sided_die

[Anthony] is a big fan of Dungeons & Dragons, but he thought the game would be far more fun to play with an electronic die rather than the traditional fare. Electronic dice are nothing new around here, though we can’t help but like his design.

He wanted to keep his electronic die as small as possible while ensuring it would last an entire gaming session, so rather than use a battery to power it, he opted for a super capacitor instead. His 1F 5.5V cap keeps the PIC18 and 22 SMD LEDs chugging along quite nicely without ever requiring a break in the action for a charge.

The electronic die looks great, and give him the choice of rolling a 4, 6, 8, 10, 12, and 20 sided die with a simple push of a button. While a bit less interactive than tossing a die on the table, we certainly wouldn’t mind having one.

Which Resistor Values Should You Order For All Circumstances?

September 28, 2011 by Mike Szczys 29 Comments

A hard drive crash, and some other happenings that aren’t entirely clear to us, led [Devbisme] to put in a parts order. As he wanted to make the most of his shipping costs, he decided to fill out the order with parts that he’ll use eventually. He’s been working with surface mount designs and wanted to move from using resistors with 0805 packages to the 0603. Having nothing on hand, he devised a way to account for almost all standard values with the fewest number of different resistors.

That’s a mouthful, but what he actually did was figure out what combinations of resistors can best be wired in parallel to achieve a different standard resistance value. This way, if he doesn’t have a specific value he can solder one 0603 surface mount resistor on top of another one to get there. He ended up writing a Python program to best calculate this set of values. It came up with a set that lets him synthesize 159 of the 168 standard resistor values within +/- 4% using just 19 actual resistor values. His method requires anywhere from one to three resistors to get to each value. Soldering three 0603 packages on top of each other might not be the most fun, but it makes for easy parts inventory management.

Turn Your Wireless Keyboard Into A MAME Controller!

September 27, 2011 by Jeremy Cook 9 Comments

For those of you that have a wireless keyboard laying around, you might be tempted to turn it into something else, like a wireless MAME controller. For those not familiar with it, MAME stands for “Multiple Arcade Machine Emulator” and is generally used to run older arcade games on a computer.

Encoders are available for this purpose, however, intending to save some money, and having an unused wireless keyboard, I decided to try to make one myself. As far as I know there are no wireless encoders available for this purpose, so that was part of the motivation for trying this.

In this post I go over my mechanical design for the cabinet as well as the electrical process of going from keyboard to MAME controller. I did eventually get the thing working, but if more than a couple buttons were pressed simultaneously, some presses were omitted. The conclusion I eventually came to was that it was better to use an encoder to control everything. Not wireless, but much more reliable. If I absolutely needed a wireless controller in the future, I would think modding an actual wireless controller (or two) in a similar manner would have worked better for my purposes.

Toilet Paper Printer Made From Scrap Parts

September 27, 2011 by Mike Nathan 18 Comments

toilet_paper_printer

Some of our favorite hacks are those made with scrap materials, so we were delighted to see a contest being held by the German technology magazine c’t which focuses on using salvaged components. “Mach flott den Schrott” is the name of the competition, which loosely translates to “Make fast the scrap”.

German builder [Mario Lukas’] entry into the contest (Google Translation) is definitely unique, and certainly fits within the theme. He built a toilet paper printer that uses a bunch of recycled components to write anything he desires on a roll of the soft white stuff. His blog walks through the build details, including a bill of materials for all of the scrap bits he used to put it together. Several CD-ROM drives, printers, and even inline skates donated some components to the printer, while an Arduino controls the entire printing process.

Though [Mario] is using RSS and Twitter feeds as a data source for his toilet-side scribe, we imagine it will only be a matter of time before advertising companies seize upon this sort of technology to create personalized advertisements geared towards a decidedly captive audience.

Continue reading to see a quick video of his toilet paper printer in action.

[via Make]

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The Water Calligraphy Tricycle

September 26, 2011 by Jeremy Cook 12 Comments

Many westerners visiting or living in China may observe the art of “water calligraphy” and some may even try to imitate it. However, media artist [Nicholas Hanna] decided to take a totally new approach and make his own water painting machine.

Someone less creative would have devised some imitation of a human, but [Nicholas] decided to totally rethink the process in the form of a tricycle. Using 16 PC-controlled water solenoids, this tricycle is turned into a sort of moving dot matrix printer. It doesn’t have the same sort of grace that the traditional Chinese art does, but it’s quite a bit faster, so if you want to get your message out, this might have some practical applications.

The post doesn’t go into the electronics, but the video after the break includes some close-ups and video of [Nicholas] assembling the device. If you happen to be in china, his tricycle is part of an event for “Beijing Design Week” at the Northern Electric Relay Factory until October 3rd.

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