Hardware Handshaking For AVR

May 17, 2011 by Kevin Dady 22 Comments

Serial communication is still an important part of our embedded world. Typically we use a 3 wire setup (RX TX and GROUND) and hope that everything goes according to plan. Though this works for most experimenters, sometimes its not the most ideal situation. This is where [simmonmt’s] handiwork comes in adding hardware handshaking to a AVR.

The hardware setup is pretty typical, an Atmega644 sits on one end of the connection, passes through a SP3232EB level shifter and out to a PC. 5 lines are used, again one for RX, TX and GROUND, but also RTS and CTS. When the PC is ready to transmit data it inverts the line (normally held high), the micro controller notices this it pulls CTS low and transmission can commence whenever it darn well feels like it. Handy!

Bluetooth Media Remote In An N64 Controller

May 14, 2011 by Caleb Kraft 5 Comments

[Phik] wrote in to share his very first microcontroller project with us. He built a bluetooth remote in an old Nintendo 64 controller to control an audio application on his computer. He had been building up the individual modules with the controller in mind for some time, but initially had no idea what kind of enclosure to put it in. After a failed attempt at stuffing it into an XBox controller(surely there was enough space), he realized he had a broken N64 controller lying around that he cold use. We think he did a fantastic job of mounting it, it looks almost like a commercial product. He documented the construction and testing of each individual module. You can find each of those broken into their own post on his site by checking out the archives. Great job [Phik], especially for your first project!

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Photon Banner

May 7, 2011 by Kevin Dady 17 Comments

The Revision 2011 demo party that brought us” table for two” a little while ago along with some super demos for PC’s, retro, and state of the art, has also brought us the Photon Banner(google translate). The Photon Banner is a 96X24 led matrix that was made with (of course) 2304 5mm leds, and a atmega 644 clocked at 20MHz.

The end result is a 192cm X 48cm display area that uses the single micro controller, that has been beefed up with 2 megs of SPI flash memory, 6 driver boards, and took about a month just to construct. The software to drive the show took another 15 days, and it is pretty darn impressive.

The website above contains a bunch of photos, parts lists, and schematics. Before you go running off you should join us after the break for a couple of quick videos.

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Thrift Store Hard Drive Enclosure

May 2, 2011 by Kevin Dady 8 Comments

[Ken] visited our site looking for case modding stuff a little while back, but more importantly he came back to show off his latest project. Using a jewelry box found at our favorite place, the thrift store, he converted it into a 2.5 inch USB drive enclosure.

Almost instantly he found that this particular jewelry box is a perfect fit for a 2.5 inch SATA laptop drive. Taking that as a sign he whipped up some acrylic mounts and cut some holes for power and USB . The electronics are provided by another enclosure with a dead drive, again acrylic is used to insulate the drive from the decorative metal box and some rubber washers were used to help cancel out vibrations and noise.

The end result is a classy looking 150gig usb drive that looks nice on the desk, and a little reminder that if your not hitting up your local thrift / second hand stores, you could be missing out on some real gems.

Cellphone Battery Mouse Modification

April 19, 2011 by Mike Szczys 23 Comments

Ever wanted to increase the battery performance in your wireless mouse? [Davetech] shows you the way with this guide for converting a mouse from AA to lithium batteries. We were delighted by his hack-tacular approach that seems to have a nice little work-around at each step in the process. He grinds down the plastic battery housing that is molded into the original mouse body, then uses an old Compact Flash card connector as a set of spring terminals for a Nokia cellphone battery. This battery has more capacity and recharges faster than non-Lithium AA cells. But unfortunately the spring terminals didn’t quite reach the recessed batter contact. No problem, he just builds up solder on the battery to bridge the gap.

[Davetech] manages to fit the entire battery inside the mouse and the pointing-device still works. Your mileage may vary by model (both battery and mouse). It is necessary to take the battery out of the mouse for recharging, but since this only happen about every couple of weeks thanks to the extended capacity it’s not too much of a hassle. Perhaps someone could carry this to the next level by adding a USB port and the necessary charging circuitry?

Fiberoptic Mouse Prevents Stray Magnetic Fields

April 15, 2011 by Brian Benchoff 20 Comments

[Ben] needed an input device that would operate where electrical signals and magnetic fields wouldn’t be tolerated, so he ended up running fiberoptics instead of electricity to a mouse.

[Ben] ran some glass fiber from the mouse to quadrature encoders to get the x and y velocity. Mouse clicks are read by modifying the existing buttons with a small shutter to block light from shining through the button frame. This isn’t the first time [Ben] adapted fiberoptics to an input device. Last year, he also built a fiberoptic joystick using the same principles.

We covered [Ben]’s DIY Electron Microscope last month, and we’re wondering if these two projects are related. His project log said he was getting distorted images from the electric field coming from his cooling fan and heater. Maybe he solved that problem and is now just tracking down every last unwanted electromagnetic emission.

Video of the mouse after the break.

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Super VMW CPU Meter

April 7, 2011 by Kevin Dady 10 Comments

After many delays, restarts, and years, [Vince ] has finally finished his Super VMW CPU Meter. Featuring six alphanumeric red led displays, two 10 segment bar graphs, twelve red LEDs, and six color LEDs its got plenty of “screen” space to show all sorts of useful information.

Electrically its driven by four SAA1064 LED driver chips attached to an i2c bus which is banged by a PC’s parallel port and driven by software in linux. The software allows you to build displays for what ever application you may want, and even includes a color ASCII output so you can see what it will look like before you even have hardware.

Four examples are given, one is a cpu meter which uses the bar graph displays to show load per core. Another uses the bar graphs as a VU meter for your music while displaying the song’s information. There is a clock in all the normal formats + UNIX time, and some scrolling text demos.

Construction gets a little odd as overhang of chips and connectors was not really taken into account so some “lofting” was needed to raise the trouble spots above the rest of the board. It is not something we would want to do, but a handy trick if we are ever faced with that situation.

Join us after the break to see this wild light show in action. Continue reading “Super VMW CPU Meter” →