Cellphone microscope for about $20

Medical-grade microscope photography for $20 might be a game changer in areas where medical services are unavailable. This particular hack uses an iPhone’s 2 megapixel camera, as well as a tiny glass marble, to magnify a sample to about 350 times its actual size. The two images seen on the left are red blood cells photographed with the improvised microscope. The main issue with this magnification method is a very thin plane of focus that is overcome with processing in software.

This makes us think of the microscope hack that shined a laser through a droplet of water, to project the image on a wall. The concept was later refined to work with samples on glass slides. There are a couple of distinct advantages to using this cellphone-based method. First, the sample can be seen with its true colors. Second, you not only magnify the sample, but you have a digitized image already on a device that connects to the Internet. If you’re trying to make a medical diagnosis this can easily be sent to a qualified professional for analysis.

The team that came up with this technique also figured out how to build a cellphone-based spectrometer for just a few bucks. The image in the upper right is the result of that hack. Both have a step-by-step build guide on the page linked at the top. The microscope is just a glass bead in a piece of rubber, as seen here. The spectrometer is a bit more involved.

[Thanks Fabien]

Multicolor 3D prints the hard way

After drooling over the Makerbot dual-head extruder, [Brett] decided to get off his duff and make a proper multi-color print.

[Brett] has been making a few bottle openers for friends and has been successfully experimenting with switching filaments in the middle of a print. For his “Saturday Killer” bottle opener, he decided to push multicolored prints to the limit. For the “Saturday Killer,” [Brett] decided to print an abridged version of the classic Simpsons quote, “Beer, the cause of, and solution to, all of life’s problems” on the side of a bottle opener in 4 different colors.

The files necessary to print the Saturday Killer were generated in OpenSCAD. The general principle behind the design is to generate separate .STL files for the bottle opener and the sides, split those files into 2-layer chunks, and print those files while constantly adjusting the z-height. It’s not called the Saturday Killer for nothing, so [Brett] had to change the color of his filament 25 times.

A much simpler version of a complex multi-color print is [Brett]‘s Shepard Fairey inspired self-portrait. Still, we’re thinking a dual head extruder is somewhere in [Brett]‘s future. At least he’s got the technique down.

Unbricking and upgrading an ASUS wl520 router


[Andrew] has an ASUS wl520-gU router that he is pretty fond of, despite its numerous problems. CPU clock bug aside, the router only has 16MB or memory like many others on the market. While tooling around with the bootloader he bricked the device, so he decided it was time for an overhaul.

After some searching online, he found that the router could be unbricked by shorting out one of the pins on its flash chip. With an emergency unbrick button installed on the board, he can now reset it in seconds by power cycling the device.

Now that he had a working router again, he proceeded to remedy his initial gripe – the lackluster amount of memory. He soldered in a 512Mbit (64MB) module in the original chip’s place, crossed his fingers and booted the router. It started up just fine, so he ran a few commands to instruct the router to recognize the new memory capacity. After rebooting, he found that it only recognized 32MB of RAM, which was remedied by soldering a 22 Ohm resistor to one of the module’s pins.

It did take a bit of careful soldering to get things upgraded and working, but we think it was well worth the effort.

Halloween Hacks: Scaring small children with Huffman coding

The team over at NerdKits decided they needed to do something for Halloween. Only on Halloween is scaring small children is an admirable goal, so they demoed a way to play creepy sounds after a door has been opened.

To trigger the sound, a magnetic reed switch from an alarm system is attached to a front door. This triggers the microcontroller and with a bit of delay, some creepy audio can be played on a pair of speakers. The team decided to store all the audio data on the flash memory of their ATmega328p, but that wouldn’t allow for a very long scream. To extend the length of the wails of the damned, the NerdKits team decided to use Huffman coded audio.

Because Huffman coding relies on the most common value being assigned the shortest code, the team used a bit of Python and C magic to figure out the optimal encoding for their audio file. After the evil laugh was sufficiently compressed, the microcontroller was programmed to decode the audio and send it to a pair of speakers. The team made all the software for their project available here for your perusal.

Although this project could be thrown together in an hour with an Arduino and an MP3 shield, the NerdKits team wants to get kids to learn how things work, also an admirable goal. [Humberto] from NerdKits put a video up explaining the theory of the project. Check it out after the break.

[Read more...]

Baking an HP LaserJet 1522 Series back to life


[Thice] had himself a problem. As luck would have it his HP laser printer died shortly after the warranty period expired, and HP was ready to charge him €350 to repair it. Since that would pretty much buy [Thice] a new one, he decided to try fixing the problem himself. He scoured the Internet for a solution to his problem, and luckily discovered that his printer might be recoverable.

The entire LaserJet M1522 series is apparently pretty prone to breaking, with the formatter board being the usual point of failure. To fix his printer, he disassembled the outer shell, removing the formatter board from the unit. Once the onboard battery was removed, he constructed a set of standoffs using aluminum foil, and set the board in his oven at 180°C (~356°F) for about eight minutes.

After cooling, he reinstalled the board, and his printer behaved as good as new. [Thice] says that the only problem with his fix is that he needs to bake the board every 6 months or so, making this a great hack but not the most ideal solution in the long term.

Beefing up your laptop’s gaming chops with an external GPU


If you’re not willing to shell out for a reasonably powerful laptop it seems that there’s not a ton that can be done to boost your gaming performance. That is, unless you have an empty Express card slot and the right chipset.

[Phatboy69] recently put together an external video card for his notebook, with fantastic results. His Vaio Z128GG had an Nvidia GT330M graphics card onboard, which is decent but nothing to write home about. Using an Express card to PCIe adapter, he added an external Nvidia GTX580 to his system, and he couldn’t be more pleased with the results. While the card does take a performance hit when connected to his laptop in this way, he claims that his graphics performance has increased ten-fold, which isn’t too shabby.

There are many variables on which this process is heavily dependent, but with the right amount of tweaking, some great laptop gaming performance can be had. That said, it really does take the portability factor of your notebook down to about zero.

If this is something you might be interested in, be sure to check out this thread over at the Notebook Review Forums – it’s where [Phatboy69] found all the information he needed to get his system up and running properly.

[Thanks, Henry]

Creating a voice controlled robotic arm


[Arthur] was laid up with a wrist injury, so he decided it would be a great time to hang out around the house and tinker with electronics, since most outdoor activities were out of the question. He picked up a robotic arm kit and assembled it to test out some code written for it that he found online. Since typing commands into a terminal was awfully cumbersome considering his injury, he figured he might as well construct a voice control system for the arm.

He documents his work in a three part series, covering the process from concept to completion. The first part centers around the creation of the vocabulary and grammar for the voice recognition system, along with the how the grammar model was trained using voice samples.

The second and third portions of his tutorial deal with the software’s decoding of his commands and the Python scripts used to translate those commands into something the robotic arm can process.

[Arthur’s] voice control system works pretty well as you can see in the video below, though he already has a wish list full of improvements he hopes to make in the near future.

[Read more...]