Hackaday Links: February 2, 2014

February 2, 2014 by 14 Comments

hackaday-links-chain

[Michel] was in need of a 9V battery connector, and in a brilliant bit of insight realized 9V batteries will plug directly into other 9V batteries (just… don’t do that. ever.) Taking a dead 9V, he tore it open, was disappointed by the lack of AAAA cells, and soldered some wires onto the connector.

Sometimes a project starts off as a reasonable endeavour, but quickly becomes something much more awesome. [Wallyman] started off building a hammock stand and ended up making a giant slingshot. We’re not one to argue with something that just became a million times more fun.

We’ve seen solder stencils made out of laser-cut metal, photoetched metal, plastic cut on a vinyl cutter, laser-cut plastic, and now finally one made on a 3D printer. It’s a pretty simple process – get the tCream layer into a .DXF file, then subtract it from a plastic plate in OpenSCAD.

Apple loves their proprietary screws, and when [Jim] tried to open his Macbook Air with the pentalobe screwdriver that came with an iPhone repair kit, he found it was too large. No problem, then: just grind it down. Now if only someone could tell us why a laptop uses smaller screws than a phone…

[Victor] has been playing around with an RTLSDR USB TV tuner dongle for a few months now. It’s a great tool, but the USB thumb drive form factor wasn’t sitting well with him. To fix that, he stuck everything into a classy painted Hammond 1590A enclosure. It looks much cooler, and now [Victor] can waterproof his toy and add a ferrite to clean things up.

Decoding News Helicopter Signals On YouTube

February 2, 2014 by 20 Comments

A serendipitous YouTube video recommendation led [Oona] to a raw copy of a news helicopter car chase video. While watching the video she noticed an odd sound playing from her left speaker. That was all it took to put [Oona] on the hunt. Decoding mystery signals is a bit of an obsession for her. We last saw [Oona] decoding radio signals for bus stop displays. She isolated the left audio channel and sent it through baudline software, which helped her determine it was a binary frequency shift keyed (BFSK) signal. A bit more work with SoX, and she had a 1200 baud bit stream.

Opening up the decoded file in a hex editor revealed the data. Packets were 47 bytes each. Most of the data packets was static. However, thee groups of bytes continuously changed. [Oona] decoded these numbers as latitude and longitude, and plotted the resulting data on Google Earth. Plotting her data against the position of the car in the video revealed a match. [Oona] had a complete track of the news helicopter as it followed the car. The telemetry data is in 7-bit Bell 202 ASCII, and is most likely part of an Interruptible Foldback (IFB) system used by the helicopter news crew and the studio producers. Click past the break for the YouTube video that started this all.

Continue reading “Decoding News Helicopter Signals On YouTube” →

A Better USI I2C Library For The MSP430

February 2, 2014 by 7 Comments

USI

TI’s MSP430 chips are rather interesting – they’re low power, very capable, and available for under a dollar in most cases. Some of these chips, though, don’t have native SPI or I2C interfaces; instead, everything is done through a USI, or Universal Serial Interface module. [Jan] found the stock I2C USI module was a little rough around the edges, so he created his own.

[Jan] found the TI example code for using the USI as an I2C device overly complicated and something that an intern whipped up in a week and was never touched again. In response to this, he created a much, much simpler USI/I2C module that’s actually readable. It’s available over on the GitHub if you want to grab it for yourself.

Compared to the TI code, [Jan]’s library is dead simple. There are only two functions, one for initialization, and another for sending and receiving. Easy, small, and it works. Can’t do much better than that.

This Space Saver Puts The Squeeze On Your Keys

February 2, 2014 by 30 Comments

MultiKey

Keys? Who needs them? Well, pretty much everyone. You can’t deny that there are some ridiculously crowded key chains out there. It’s clear that [Robb] wanted to hit the other side of that spectrum when he started working on his latest multi-key project.

The term “multi-key” may be a little misleading as there are more than just keys on this tool. In addition to the bike lock, locker, work and house keys, there is a USB drive, bottle opener, screw driver and a couple of Allen wrenches. The side frames started out as part of an Allen key combo set; one not of the highest quality.  The Allen keys started snapping off during use which left [Robb] with a set of otherwise useless side frames. These became the platform of which [Robb’s] project is based. Adding a couple new bolts, nuts and a few modified keys got him the rest of the way there. A lot of thought went into which items to put into this tool and [Robb] explains his thought process in his step-by-step instructions.

The simple nature and potential for customizing makes this a great utilitarian DIY project. Although this may not be Janitor worthy, it will certainly consolidate some of the bulk in our pockets.

The Most Horrifying Use Of 3D Printing

February 2, 2014 by 38 Comments

As anyone with a Facebook account that’s over the age of 25 will tell you, 3D ultrasounds of fetuses are all the rage these days, with ultrasound pictures of the unborn recently taking the leap from black and white blobs to 3D – and 4D – images. With the advent of 3D printers, the inevitable has happened. Now you can order a 3D print of your yet-to-be-born progeny.

The company behind this – 3D Babies – takes 3D ultrasound data from weeks 24-32 and turns it into a 3D model. The printed 3D models sell for $800 for the full size version, $400 for a half-size version, and $200 for a quarter size version. It appears the 3D ultrasound data is simply wrapped around a pre-defined mesh, so while the resulting print may come out looking like your spawn, it’s still not a physical copy of the 3D/4D ultrasound data.

Despite the ‘creepy’ factor of these little bundles of plastic, we’re wondering why we haven’t seen anything like this before. Are there any obstetricians/radiologists/ultrasound techs out there that have experience with importing 3D ultrasound data into an editor of some sort? Notwithstanding any HIPAA violations, it seems it would be rather easy to turn this sort of 3D data into a printed object. 3D printing CT scans models can’t be the only other instance of this type of thing.

Thanks [Will] for the nightmares

Rewriting WS2812 Driver Libraries For Optimization

February 2, 2014 by 14 Comments

ws2812_compared

We like [Tim’s] drive for improvement. He wrote a WS2812 driver library that works with AVR and ARM Cortex-M0 microcontrollers, but he wasn’t satisfied with how much of the controller’s resources the library used to simply output the required timing signal for these LED modules. When he set out to build version 2.0, he dug much deeper than just optimizing his own code.

We remember [Tim] from his project reverse engineering a candle flicker LED. This time, he’s done more reverse engineering by comparing the actual timing performance of the WS2812(B) module with its published specs. He learned that although several timing aspects require precision, others can be fudged a little bit. To figure out which ones, [Tim] used an ATtiny85 as a signal-generator and monitored performance results with a Saleae logic analyzer. Of course, to even talk about these advances you need to know something about the timing scheme, so [Tim] provides a quick run-through of the protocol as part of his write-up.

Click the top link to read his findings and how he used them to write the new library, which is stored in his GitHub repository.

Oscilloscope Repair Projects Still Probing For Success

February 1, 2014 by 35 Comments

lecroy-9450-oscilloscope-repair[Luke] isn’t able to declare total victory yet. His LeCroy 9450 oscilloscope repair project has seen some success, though. The glitchy screen seen above is just one of the problems it had, but has now been fixed. When [Luke] got his hands on it, this was one of three screen states: the other two being normal operation or completely dead. Replacing the screen connector was all it took, so he moved on to the second part.

This one is much less trivial. Only one of the two channels works—which might be the point at which many would abandon the repair—but it’s still a fine single-channel scope. [Luke] continued to trouble-shoot by disassembling the bottom of the case and breaking out the device’s schematics. He traced the circuit and found one module that is suspect (and is looking for help finding a replacement). Unfortunately, the problems don’t end there. Another unknown problem is causing erroneous signals on the displayed waveforms. It’s an odd issue but it really feels like he’s close to solving this one!