Looking for more ways to enhance his 3D printer, [JJ] decided to make it wireless. He got his hands on some $10 Bluetooth modules and figured this would be just the thing to make the link with his laptop.

They came as surface mount modules, so the first thing he had to do was develop a breakout board that he could patch into his Ultimaker 3D printer. This provided a nice opportunity as he needed to do some level converting to make the 3.3V module play nicely with his 5V CNC electronics. The first version of the board turned out well but he had really a poor communications range. The second version, which is pictured above, hangs the module’s antenna off the edge of the breakout board and works a lot better.

We’ve embedded a clip after the break that walks through the development of this board. [JJ] shared the Eagle CAD files as a megaupload link, but we’ve also mirrored the file after the break for your convenience.

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[Ben Laskowski's] been working on a Class-D audio amplifier for several months. What you see above is the most recent version of the amp. A class-D amplifier uses transistor switching (or in this case MOSFET switching) to generate the pulse-width-modulated signal that drives the speaker. This is different from common amplifiers as it doesn’t generate the kind of heat that traditional amplifiers do, making it much more efficient.

After the break you can hear it demonstrated. It’s operating off of a single-supply laptop brick and we do hear a bit of a hum coming through the system. Still, we’re quite pleased at the power and quality the small board can put out. Take a look at a post from November to get a handle on what went into development. If you still hunger for more details, [Ben's] shared the bulk of his prototyping materials in the github repository.

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If you don’t have an oscilloscope you’d be surprised how many times you find yourself needing one. But if you have an Arduino on hand, the next time you might be able to get by with this software suite that can use a development board as oscilloscope inputs. The project is called xoscillo, and it allows an Arduino, or a Parallax USB Oscilloscope, to probe the signals while a computer does the heavy lifting.

The Arduino can be used for up to four input channels at 7 kHz. It’s possible to probe seven signals at 4 kHz as well. But the main feature that caught our eye is the ability to use several Arduino boards at one time in increase the number of channels available to you.

Granted, this is pretty slow for many digital electronic troubleshooting needs. But at least it’s something you can pull out when you just don’t have any other ideas about what is going wrong with your prototype circuit. We’re sure that sooner or later you’ll break down and buy a proper hackable oscilloscope. After all, your Arduino is probably already occupied as an I2C sniffer.

[Thanks Adam]

[Keith] wanted to use his makerbot for some PCB milling, but he ran into a pretty big problem. The platform that his PCB would sit on was mounted with a layer of double sided foam tape and was not perfectly aligned to the head. Not only that, but it would tilt when pressure was applied. This made the result of the milling completely unacceptable. To remedy this, he made a new platform that is not only rigid, but he has made it so that there is the ability to adjust it for perfect alignment via adjustment screws in the 4 corners. At the beginning of each session, he can be absolutely sure that everything is aligned perfectly and his PCBs show a huge improvement. You can see a comparison of the two in the following picture.

[via HackedGadgets]

[Johngineer] found himself in need of an I2C sniffer, but didn’t have one available. Necessity is the mother of invention, so he put together this I2C sniffer sketch for Arduino. The arduino will record what is going on for a set time interval, then dump the data via serial as a .csv. You then have to plot it to see what is going on. [Johngineer] recommends Livegraph, since it is portable and easy. As you can see in the code, the time interval is adjustable, but you have the physical limitations of the RAM on the board to consider. This seems like a pretty handy piece of code stored around, effectively giving you a passable I2C sniffer in a pinch.

It’s a madhouse already at the 2011 Bay Area Maker Faire. Though the show doesn’t officially start until tomorrow, Friday is “Education Day”, a special preview for local schools. As makers scramble to set up their displays, a thousand impressionable young minds seek the most cacophonous mixture of taiko drumming, ArcAttack’s musical Tesla coils, and the beeping and booping of the R2-D2 Builder’s Club.

This deathstar like ball is actually an autonomous surveillance camera. [Basil] wrote in to tell us about it. The body is custom designed for the project, then 3d printed.  It can be dropped anywhere, as it is battery powered for up to a month,  and communicates via cellar networks.  It checks an email folder once an hour and responds to any requests with a snapshot of what is going on. In the video, which you can see after the break, he gets an immediate response.  You can download the sourcecode as well as the files for the enclosure here.

If you wanted to reduce costs, that case could be done away with, but we suspect it helps with some moderate weather conditioning. We would also love to see a version that rotated around that equator on command for better pictures. Great job [Basil].

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[Chris] sent us this fantastic tutorial, introducing beginners to H-bridge motor drivers. While many of you will consider this stuff basic, those who are trying to expand from building only things the arduino board can handle to bigger more expansive (and powerful) projects will find this quite helpful.  [Chris's] tutorial is very in depth, not only going through the construction of the basic circuit but also showing you how to make your own PCB.  Pop on over there and learn some theory and some practice. Then you can build that battle bot you’ve always been dreaming of!