Macro Assembly For AVR Chips

December 12, 2012 by Mike Szczys 20 Comments

avr-macro-assembly

Here’s an interesting tip that can help improve your ability to write assembly code. In an effort to remove the complexity of assembly code for an AVR project [Quinn Dunki] figured out how to use macros when writing AVR code with the GNU toolchain. Anyone using AVR-GCC should keep this in mind if they ever want or need to pound out a project in assembly language.

If you look at the code snippet above you’ll see two commands that are obviously not assembly; PulseVRAMWrite and DisableVRAMWrite. These are macros that direct the assembler to roll in a hunk of code. But avr-as, the assembler used with this toolchain, lacks the ability to handle macros. That’s too bad because we agree with [Quinn] that these macros make the code easier to read and greatly reduce the probability of error from a typo since the code in the macro will be used repeatedly.

The answer is to alter the makefile to use GNU M4. We hadn’t heard of it, but sure enough it’s already installed on our Linux Mint system (“man m4” for more info). It’s a robust macro processor that swaps out all of her macros based on a separate file which defines them. The result is an assembly file that will play nicely with avr-as.

Her implementation is to help in development of the GPU for her Veronica computer project.

Twitter Radio

December 12, 2012 by Mike Szczys 12 Comments

This anthropomorphized wood bowl will read Tweets out loud. It was built by [William Lindmeier] as part of his graduate work in the Interactive Telecommunications Program (ITP) at New York University. View the clip after the break to see and hear a list from his Twitter feed read in rather pleasant text-to-speech voices.

The electronics involved are rather convoluted. Inside the upturned bowl you’ll find both an Arduino and a Raspberry Pi. But that’s not the only thing that goes into this. The best sounding text-to-speech program [William] could find was for OSX, so there is a remote computer involved as well. But we think what makes this special is the concept and execution, not the level of hardware inefficiency.

The knob to the left sets the volume and is also responsible for powering down the device. The knob of the right lets you select from various Twitter lists. Each turn of the knob is responded to with a different LED color in the nose and a spoken menu label. You can get a quick overview of the project from this summary post.

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LiPo Internal Resistance Measurement Tool

December 12, 2012 by Mike Szczys 13 Comments

lipo-internal-resistance-meter

This is a scratch-build meter for measuring the internal resistance of Lithium Polymer cells. [Bleuer Csaba] uses the LiPo cells for RC vehicles and thet take quite a beating from the motors they’re supplying. This means that he only gets about 100-200 cycles out of each cell. To figure out where one is in its life cycle you can measure the internal resistance where a rising resistance indicates greater age. [Bleuer] mentions that you can buy a meter to do this for you, but what fun is that?

Since he’s rolling his own tool he defined his own parameters for the readings. After experimenting with different loads driven for different test periods he was able to extrapolate an equation that estimates the resistance measurement. As you can see in the clip after the break, this happens very fast. All he has to do is connect the cell and press one button. The measurements are made and various data points are displayed on the quartet of 7-segment displays.

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Super Slim Wristwatch Build

December 12, 2012 by Mike Szczys 33 Comments

This slmwtch lives up to its name. When the LCD screen is folded back onto the PCB the entire thing comes in at just 2.35mm. That’s including a coin-cell battery not shown above. Wow!

Part of what makes this possible is the specialized PCB design. [Anders] didn’t want to add more thickness than the screen and battery so he make a cutout in the PCB design to accept each component. In this image it’s easiest to see on the two SMD resistor in the upper left. They’re held in a void by the two solder connections. Admittedly this is not going to be a mass-production friendly design. And we have concerts about the long-term stability of suspending components by their leads. But as a one-off it’s fantastic! See for yourself in the video after the break.

The control for the watch uses two touch sensitive pads on the back of the PCB. There is no backlight for the display which can be a problem when trying to read the time while outdoors. We wonder if an ePaper display with similar dimensions is available?

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Unlocking Verizon Galaxy Note II And Galaxy S3

December 12, 2012 by Mike Szczys 13 Comments

galaxy-note-II-verizon-unlock

[Adam Outler] and friends have been hard at work unlocking the bootloader of some Verizon Android devices. His most recent adventure involves unlocking the Verizon branded Samsung Galaxy Note II.

You can’t run Cyanogenmod on a device that has a locked bootloader. This is presumably why it took no time at all for the XDA forum users with Verizon phones to raise enough money to put one of these puppies in [Adam’s] hands. He walks through the process he used to find the exploit in the video after the break. We’re not experts on the process, but apparently the .pit file used when flashing Odin is the entry point for the exploit. A bit of code has been injected into it which provides an opening to flash a replacement bootloader.

We mentioned the Galaxy S3 in the title. Apparently that has been unlocked as well but with one big hang-up. An over-the-air update could possibly brick the S3. To avoid this issue with the Galaxy Note II the original bootloader is patched and reflashed as part of the exploit.

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Observe A Satellite’s Morse Code Message Today!

December 12, 2012 by Mike Szczys 58 Comments

Niwaka1-satellite

If you live in the Eastern portion of the United States and the skies are clear you can see a student built satellite flashing LEDs in Morse Code today. But don’t worry. If you it’s cloudy or if you live elsewhere there are several other opportunities to see it in the coming days.

This is the Niwaka Fitsat-1. It was developed by students at the [Fukuoka Institute of Technology] and deployed from the International Space Station on October 4th. Included in the payload is an array of LEDs seen in the image above. On a set schedule these are used to flash a Morse Code message for two minutes at a time. That is what’s shown in the image on the upper right.

You can look up information on seeing Fitsat-1 in your own area using this webpage. All of the observation windows in our area require a pair of binoculars or better. We’re not sure if there is any case in which this can be seen by the naked eye.

[Thanks SWHarden and KomradBob]

Tablet Rig Takes Sheet Music Digital

December 12, 2012 by Mike Szczys 12 Comments

music-stand-tablet-holder

[Bill Dudley’s] wife wanted to use a couple of different tablets for displaying sheet music. Sure, a proper music stand will have no trouble supporting the weight of the device, but if it’s not secured it place you may soon have a broken device. [Bill’s] solution was to build this tablet stand out of PVC.

The image above doesn’t tell the entire story of how he did this. But if you look really closely you’ll notice that the pipe is actually acting as a frame rather than a cradle. After measuring, cutting, and gluing all of the components together he cut a channel around the inside of the u-shaped PVC frame. The channel is the exact thickness of the tablet and holds the device securely. A base from a music stand makes up the rest of the rig.

Pages can be turned using a USB foot pedal. This is fantastic for gigging musician who use digital music collections like the Real Book.