Adjustable Prank Box Growls And Screams

April 3, 2011 by Mike Nathan 6 Comments

growling_altoids_tin

[Brett] over at FightCube was tossing around ideas to build a screaming prank circuit that fits inside an Altoids tin. Sound familiar? We featured a story just a few days back about the construction of a very similar item by [Dino Segovis]. It seems that great minds think alike after all!

[Brett’s] version is a bit more robust than the one we featured the other day. It’s similar to [Dino’s] in that it uses a 555 timer in astable mode, triggered by a normally-closed microswitch when the tin is opened. However, this version also includes a photoresistor which is used to increase the pitch and speed of the output as more light enters the box. This creates a growling effect that builds up into a scream as the box is opened. [Brett] has also included an adjustable pot which allows the sound range to be tweaked to his liking.

Stick around for a video walkthrough of the screamer circuit as well as a demo of the Altoids tin in action.

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Simple DTMF Decoder Pulls Numbers From YouTube Videos

April 2, 2011 by Mike Nathan 28 Comments

dtmf_decoder

While many of us have banished land line telephones from our houses, there are still quite a few people who utilize POTS lines today. These analog phone systems use Dual Tone Multi Frequency (DTMF) signals in order to audibly represent all of the keys on a telephone keypad and place calls. [Brad] over at LucidScience decided that it would be useful to have a DTMF decoder on hand, and got busy building one.

His DTMF decoder box uses a CM8870 DTMF decoder chip, which you might assume is all you need to get the job done. This chip performs its duties very well, outputting a 4-bit binary code for each button press it registers, but that doesn’t do a whole lot of good without being able to represent those codes in a meaningful fashion. He first built a breadboard decoder circuit that would light 1 of 16 LEDs depending on the detected button press. This was well and good, but he decided that an Arduino-driven LCD display would work far better.

When he was finished, he had a compact decoder box with an LCD display, which accepts input from either an RJ-11 cable or an audio jack. He says that the audio jack is particularly useful for decoding tones from computer audio, such as YouTube clips. [Brad] praises the CM8870 chip, stating that it can pull phone numbers from pretty much any audio or phone signal you throw at it, regardless of quality. We think it would make a great basis for a telephone-based security system, if that was something that appealed to you.

Be sure to stick around to see his DTMF decoder circuit in action.

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3D Printer Gets A Big Resolution Improvement

April 1, 2011 by Mike Szczys 48 Comments

[Jose Carlos Veloso Junior] has been working on his 3D printer to improve the resolution. We looked in on his project back in October when he was printing the blue busts like the one seen above.

We were impressed by the resolution he was able to achieve back then, using liquid resin that is cured with visible light. The resin creates a thin layer on a glass tray, and is cured when a projector shines precisely positioned light from below. The cured resin is then lifted on the Z-axis, and the next layer in the printing process is hardened by the projector’s light.

Well, this newest rendition far outperforms the initial iteration. The bust on the right looks like it’s been hand-buffed to remove the layer lines, but it actually just came off of the printer. [Jose] made a video of the new equipment in action, which you can watch after the break. He’s keeping most of the juicy bits to himself but he did tell us that the improvement he achieved were due to multiple changes in the process. He tweaked the software to use a more precise curing time, the resin formula has been improved, the ability to isolate pixels without hardening resin around them has been stepped up, and he’s made changes to the way the printer is calibrated and how it lifts the hardened model.

This is fantastic. Kudos to you sir!

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Kinect Produced Autostereograms (Magic Eye Pictures)

April 1, 2011 by Mike Szczys 8 Comments

[Kyle McDonald], working collaboratively with [Golan Levin] at the Studio for Creative Inquiry, has come up with an application that can produce autostereograms. These are pictures that appear to be three-dimensional thanks to a visual illusion created by forcing your eyes to adjust focus and vergence differently than they normally would. The program is called ofxAutostereogram and it comes with a couple of examples. Both are show in [Kyle’s] video (embedded after the break), starting with a depth image of a shark. This combines with a texture tile, then is processed through the openFrameworks software in the package to produce the final image.

If that’s all it did you might find it rather unimpressive… these images have been around for some time although they were never so easy to produce on your home computer. But the second example is a pretty fantastic one. You can use a depth image from a Kinect as the starting point. As seen above, there is a preview window where you can adjust the clipping planes in order to include the correct depth. This also allows you a preview of your pose. Once it’s just right, snap a pick and process it through the software.

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Thanks For Ruining A Good Thing, Or TRYING To!

March 31, 2011 by Kevin Dady 44 Comments

It seems that there has been some shenanigans happening with the OSHW logo voting page as some are using scripts to game the system for their favorite design. Why? Who knows… How? Well one of the advocates of OSHW [Bill Porter] set about figuring that out, and things should be patched up now, though that still leaves 3,122 faulty votes to weed out on the final day (April 5^th).

While it is hard to imagine how someone would be so attached to a logo to write a script just to game votes, its not that surprising considering that we can be a pretty outgoing bunch when it comes to certain topics. Organizers are asking if you’re one of the listed IP addresses, and had good intentions to fess up, and tell which logo(s) you voted for to make the process easier. If not, well, “this is not going to stop everyone’s good efforts.”

If you’re just now getting wind of the OSHW logo voting check out our previous article highlighting this event, and to get more details.

Screaming Altoids Tin Just In Time For April Fool’s

March 31, 2011 by Mike Nathan 13 Comments

altoids_screamer

Maker [Dino Segovis] has started on a project he calls “Hack a week” where he will be putting together one hack or project per week, for a full year. The first installment of his video series was finished just two days before April Fool’s, and appropriately enough covers the construction of a circuit you can use to prank your friends.

The “Altoids Screamer” is a simple circuit based on a 555 timer that he built into a standard Altoids Tin. The 555 timer is used to generate a loud pitched squeal whenever the tin is opened. This is accomplished by wiring up the 555 in astable mode, and connecting it to a speaker to output the sound. A micro switch is installed inside the tin to detect when the top has been opened, triggering the “scream”.

While it’s not the most complex circuit we’ve seen, it definitely gets the job done and is easy enough to build in time for tomorrow’s festivities. It is a great hack for the office, the library, or any other quiet place.

Continue reading to watch [Dino’s] first Hack a Week video demonstrating the prank’s construction. If you are interested in some more of his work, be sure to check out this automatic ball launcher and this other 555 Screamer toy.

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PCBs Without Any Substrate

March 31, 2011 by Mike Szczys 52 Comments

[Kimio Kosaka] is taking the concept of free-formed circuits to the next level with O’Baka Project No.7. It’s a fully functioning Arduino board, without the board. The traces are there and provide all of the support for the rest of the hardware. You can imagine the fragility of the package so it won’t be a surprise to learn that O’Baka Project means ‘stupid’ project.

We don’t think this manufacturing process is completely worthless. The ‘board’ seen above looks quite interesting and might be a good idea when building a show-piece where you want the circuitry to be seen. [Kimio] describes the process he used to achieve this look. The first step is to design a single-sided circuit board; he used EagleCAD. After printing out the traces he used 0.46mm steel wire to trace out each connection. Now heat up that soldering iron – [Kimio] recommends using high-acid flux to ease the process of soldering to the steel.

We think this would nicely compliment projects like LED cubes that use the circuit itself as a support structure. See this Arduino alternative from several different angles in the video after the break.

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