Hack-a-Day

Around this time last year, [KopfKopfKopfAffe] was enlisted as a set designer and was told to build some sort of light effects for electronic music parties. The budget for the project wasn’t much at 200 Euros, but he did manage to build decent 5×5 RGB LED matrix that is fully controllable by a computer.

[KopfKopfKopfAffe] didn’t have the time or money to wait for manufactured PCBs, so a bunch of perfboard was placed in a CNC mill with a pen to act as a plotter. All the lines that needed soldered were drawn on by the mill, a feat that probably saved hours of looking at the design before committing solder to iron.

A total of five boards were constructed, each one capable of controlling five RGB LEDs. Each board can be dasiy-chained with an RS-232 serial connection for further expansion. The only thing that’s needed to control the matrix is 17 bits that includes an address and RGB color data for each LED. The system only cost about 10 Euros per node, but we think that could be significantly reduced by leaving out the Molex and DB-9 connectors. [Kopf] project turned out very nice, check it out after the break.

Although we’re sure they exist, we wouldn’t want to meet anybody that can’t look back fondly on the halcyon days of youth that included playing hide-and-go-seek. Some kids never grow up and continue the tradition with geocaching or orienteering, but that sense of limitless discovery wanes over time. [Kurt] came up with a small scavenger hunt beacon that brings back the unending wonder that accompanies the unknown.

The beacon is just a simple ATtiny13 that flashes a message with an invisible IR LED. To receive the messages, [Kurt] made a scavenger decoder shield for an Arduino. The decoder includes a phototransistor and a 20×4 LCD display. All [Kurt] needs to do is hold the decoder up to the beacon for the text in the firmware of the ATtiny to be displayed. The beacon is only one inch square and powered by a watch battery, so it can be hidden anywhere.

[Kurt] suggests that the text of one beacon should provide the clue to the next. We’re thinking this is just a great excuse for a walk in the park. You can check out [Kurt]‘s IR decoder getting data from a beacon after the break.

Nearly everyone has heard of phantom limb syndrome. It occurs sometimes after a limb is amputated, but the mind of the patient still thinks that the limb is attached. Generally regarded as a mix-up in the wiring of the damaged nerves, a phantom limb can be very painful. [Ben] has been working on a way to alleviate some of the pain and frustration associated with a phantom limb and fortunately for us he went for a Kinect, VR goggles, and gyroscope build.

Today, most therapies for phantom limb syndrome use a Ramachandran Mirror Box. The theory behind the mirror box is pretty simple – if someone recently lost a hand, just insert one hand in one side of the box and the arm stump on the other side. Looking into the box from the side with the good hand will trick the patient’s brain into thinking the amputated hand is still there. It’s a good therapy that has been very successful, but [Ben] thought he could do something that is a little more immersive.

[Ben]‘s project uses a Kinect and VR goggles to put the patient in a virtual environment. With the help of a few gyroscopes, the patient gets a virtual representation of their whole self projected into their goggles. The technique isn’t terribly different from VR phobia treatment, although there’s much more electronics and math involved in [Ben]‘s build. The first test subject said his pain was going down, so it looks like he might have a success on his hand (no pun intended).

Check out the demos of [Ben]‘s treatment plan after the break.

[William] developed this temperature candle as a tool to help keep babies safe as they sleep. It seems that ambient temperature has an effect on Sudden Infant Death Syndrome (SIDS). This device is meant to alert you when room temperature is outside of the recommended envelope.

The board hosts an eight-pin PIC microcontroller (12F683P), a temperature sensor, RGB LED, and a push button. The round PCB is the same size as a votive candle, which is nice except that you’re going to have to drill a hole in your candle holder to accommodate that barrel jack.

The temperature sensor is read by the microcontroller and used to determine the color of the LED. Red is hot, blue is cold, and just right is somewhere in between. But if you’d rather know the exact current temperature you can press the button and it’ll blink out the Celsius reading using blue for 10 degree increments (three blinks is 30 degrees, etc.) and red for single degrees. Don’t miss the demo of the candle in the video after the break.

[Andrew] was left wanting by the slow hard drive in his 2011 Mac Mini. He set out to add a 10,000 RPM drive and we think he did a great job of pulling it off. Luckily he also took the time to document the process so you can try it yourself.

As with a lot of Apple products, a big part of this hack is just getting the darn thing apart without breaking something. Once that’s done, you’re got to do a little bit of interface hacking. To save space Apple uses a non-standard SATA breakout cable so [Andrew] starts by ordering a second hard drive cable from the company. He then soldered a thin wire connecting 12V from the motherboard to the 12V pin on a SATA connector. From there it’s just a matter of altering the original hard drive sled to make room for the 500 GB WD Velociraptor drive. It fits below the original and serves as additional space instead of as a replacement.

[Patrick] decided to make a computer controlled etch-a-sketch. While the idea is not that new, there is always a different way to accomplish a goal. An Arduino is used to control a pair of stepper motors which were sourced for pretty cheap, and even came with their own driver. Next a stand was mocked up using foam board, which helps determine where all the parts should live.

Next was a way to attach the steppers to the knobs, gears would be used and a collet meant for model airplanes was sourced to make the mechanical connection between gear and shaft. With everything set in place via foam board and paper printouts, it is off to get some thin plywood. The plywood is sent though a laser cutter creating most of the stand and gears. Now its all software, a program was whipped up for OSX which converts low res pictures into squiggly lines perfect for the etch-a-sketch to draw on its screen.

The results are quite impressive, join us after the break for a quick video.

[hackitbuildit], from instructables, has brought us a a DIY windows 8 tablet. To make the tablet, an old laptop is used that meets the minimum requirements of windows 8 preview, a touch screen conversion kit, and of course the software itself. The laptop is first prepared by removing the casing around the screen, and if you just go by the pictures it kind of looks like he is ripping it apart! Though if you look at the video screws are being removed.

The screen is flipped around and laid on the keyboard with a couple spacers between them, as many laptops use the keyboard area as heat sinking. The touch screen is installed, and some wood strips are hot-glued to the outside to fill in the gap between the screen and base. With a little paint you’re left with a large, but functional windows 8 tablet to get started developing for.

[Dan] had been wanting a pair of Bluetooth headphones for quite a while. Most of the reviews for wireless headphones in the $50-$80 range complained of tinny sound and dropped bass. Nevertheless, he stumbled upon a $20 pair of headphones with similar reviews and realized that he could switch out the driver and make a decent pair of cans.

The donor drivers came from a pair of Sennheiser HD 540 headphones. These are very respectable headphone speakers that cost about what you would expect for pro audio gear. To to get Bluetooth working with the Sennheisers, [Dan] removed the PCB and battery enclosure and attached them to the headband with velcro.

For his build, he had to cut the cable on the Sennheisers and solder them to the Bluetooth board. There was never any danger of ruining a good pair of headphones, though. If he screwed up he was only out a headphone cable. Now [Dan] has a nice pair of Bluetooth headphones that can reproduce bass. Not a bad deal for a $20 pair of headphones.

At Hack a Day, we don’t throw the term genius around lightly. We’re obligated to bestow that title on [Don Gilmore] for his amazingly simple self-tuning piano. To appreciate [Don]‘s build, you need to realize that just because a piano has 88 keys, that doesn’t mean it has 88 strings. Treble notes have three strings per key while tenor and bass notes have one or two strings each. This usually comes out to more than 200 strings per piano, and [Don] can bring them all up to tune in under a minute.

[Don]‘s system needs to perform two functions. The first one is sustaining the strings so the computer can ‘hear’ the strings. He does this with a magnetic sustainer that is a lot like an E-Bow. To bring the strings up to the right pitch, there are small heaters underneath the pin block. Running a little bit of current through these heaters allows [Don] to decrease the tension of each string and lower the pitch.

This tech reminds us of the Gibson Robot Guitar, a self-tuning guitar that does it’s trick with motors in the tuners. The Gibson didn’t do well on the sales floor, given that everybody and their mom can tune a guitar. Pianos, though, are another story. [Don] is looking for investors to bring his idea to market, and we hope to see it on the floor of a music shop sometime in the future.

Yes, an REO Speedwagon reference. Only slightly ashamed, if you’re wondering.

After a few months of eager waiting, [Brook Drumm] has finally released the files for his paradigm-shifting 3D printer, the Printrbot. If you didn’t order one of these during the Kickstarter, you can now print your own set of parts.

[Brook] gave his Printrbot to the world last November with the promise of being extremely cheap, extremely easy to build, and having a relatively high print quality. The simplicity of the Printrbot was amazing, which probably led to the Printrbot getting $830k worth of funding on the initial Kickstarter. Although the files for the 3D printed parts are out in the wild now, there still aren’t any instructions on how to build it apart from a Flickr slideshow.

[Brook] promised to release the files for the Printrbot much earlier, but we’re guessing he’s been busy printing and assembling  the 1200 Printrbots that were claimed in his Kickstarter. While we’re on the subject of cheap 3D printers, [Richard Sum], the English gent behind the SUMPOD sent in a link of one of his $600 printers milling MDF and extruding for seven hours straight. We’re on the cusp of Star Trek-style replicators here, people.

If you’ve ever wanted your own self-driving car, this is your chance. [Sebastian Thrun], co-lecturer (along with the great [Peter Norvig]) of the Stanford AI class is opening up a new class that will teach everyone who enrolls how to program a self-driving car in seven weeks.

The robotic car class is being taught alongside a CS 101 “intro to programming” course. If you don’t know the difference between an interpreter and a compiler, this is the class for you. You’ll learn how to make a search engine from scratch in seven weeks. The “Building a Search Engine” class is taught by [Thrun] and [David Evans], a professor from the University of Virginia. The driverless car course is taught solely by [Thrun], who helped win the 2005 DARPA Grand Challenge with his robot car.

In case you’re wondering if this is going to be another one-time deal like the online AI class, don’t worry. [Thrun] resigned as a tenured professor at Stanford to concentrate on teaching over the Internet. He’s still staying at Stanford as an associate professor but now he’s spending his time on his online university, Udacity. It looks like he might have his hands full with his new project; so far, classes on the theory of computation, operating systems, distributed systems, and computer security are all planned for 2012.

Apparently, there’s some sort of sporting event being televised this weekend that has been historically used as an excuse to buy a big-screen TV. [Joel] wanted a huge-screen TV on the cheap, so he converted an overhead projector to something he can use with his XBox.

Using a bare LCD panel with an overhead projector is a decades-old hack we’ve covered before. The basic idea is fairly simple, but we’ve never seen anything that could be considered a semi-permanent build. [Joel] started his project by picking up a surplus overhead projector for $25 and routing a cutting board to mount the LCD in. The bulb in the projector added a lot of heat, so three small fans are used to blow air between the projector glass and the LCD display.

[Joel] started off looking at the LumenLab DIY projector project, but considered that to be a terrible amount of work with a fairly high initial investment. If you don’t count the few LCDs [Joel] burned through while building his project, his projector was built for under $100. We’re loving the result and are sure it will be much appreciated at [Joel]‘s LAN parties.

[Arpad] has spent quite a bit of time reverse-engineering a home automation system, and, as he is quick to point out, presents the information learned for informational purposes only. He’s really done his homework (and documented it well), looking into the US patent application, and figuring out how the protocol works.

If you’re wondering how someone is able to send a signal over an AC sine wave, at least one technique is the proprietary [Universal Powerline Bus]. This works by sending precisely times pulses in conjunction with the wave that would exist normally. Given the correct software on the other end, this can then be decoded and used for whatever data transfer is necessary.

Although as engineers and technologists, we certainly don’t condone stealing patents,  part of point of one is that others are allowed to learn your secrets in exchange for some legal protection. [Arpad]‘s motivation in doing this is that the technology is only widely available in the US with our puny 120 VAC 60Hz power. With this knowledge, he’s been able to transfer it to work with European 230 VAC 50Hz.

[Yuhin Wu] wrote in to let us know about the Automated Recycling Sorter that was built with a group of classmates at the University of Toronto. They entered it the school’s student design contest and we’re happy to report that it took first place.

The angled sled has been designed to separate glass, plastic, and metal containers. The first sorting happens at the intake area. A set of moment arms are used to weed out the glass bottles. Since there are several of them in a row, a larger and heavier plastic container will not be falsely sorted and the same goes for smaller glass bottles.

With the glass out of the mix the team goes on to separate metal and plastic. An Arduino was used for this purpose. It senses an electrical disturbance caused by a metal can passing through the chute and actuates a trap door to sort it. Plastic has no effect on this sensor and slides past the trap to its own sorting bin.

Don’t miss both demo videos which we’ve included after the break.

Have you ever seen an LED display made out of routers? [Sean] took eight Netgear routers and made an 8×4 display out of them. Because that wasn’t cool enough, a very small version of Conway’s Game of Life was added to the build.

Each router is running a copy of OpenWrt, a Linux distro meant for limited hardware. Instead of an 802.11 protocol, each router runs the B.A.T.M.A.N. advanced mesh protocol. This protocol allows each router to communicate with all the other routers.

Instead of each router receiving data from a master, the routers calculate each step in the Game of Life independently.  Once the routers communicate their initial states, each router is responsible for displaying its four LEDs for each new generation. In the video after the break, you can see [Sean]‘s routers calculating random Game of Life boards. Sadly, we didn’t notice a GoL oscillator being randomly generated, but with a 4×8 play field even a Glider wouldn’t last very long.

Another week has come and gone and that means that it is time for our week in review. These are the top posts that have been viewed at Hackaday in the past week.

Coming in at first place is a post about a project by [Red Jones] and [Brian Kast] of Sandia labs. Ethical issues aside, this is a pretty cool project. They have developed a bullet that can be shot out of a smooth-bore gun that can hit within eight inches of a target one kilometer away. That is pretty amazing. It does this magic with an 8-bit processor. This takes the microcontroller wars to a whole new level. Are they using Microchip, Atmel or (gasp) something else?

In second place is a follow up post to our post asking how to control three LEDs with three switches, all in series. That post, although it was posted in December 2011 came in at number three. Getting back on topic though, this week’s post shows how he did it! Not only that, but it shows the extent that he went to when making it. There is footage through the eyepiece of a microscope showing him building one!

Want to use LiPo batteries in your next project but are afraid to use them? Here is a post where [Paul] shows off a circuit that he built that can charge LiPo batteries using a MCP7813 chip from Microchip.

Finally, rounding out the five is a post about a blog that was taken down but luckily not before the IEEE made a copy of it. This blog was made by a robot operator working at the Fukushima nuclear plant and detailed their ongoing cleanup operations there.

The sales team in [Chuck’s] office is a pretty competitive bunch as you might expect, and they decided that they wanted a system which would allow them to challenge one another during their weekly meetings. The competition involves answering questions posed by their manager, but hand raising only works for so long – they needed a definitive way to tell who “buzzed in” to answer a question first.

Since [Chuck] only had a short bit of time and a tiny budget to work on, he opted to find the easiest solution to the problem, which was an Arduino-based game show buzzer system. The game display is built from an Arduino, some LEDs and an Altoids tin, while the buzzer pushbuttons were salvaged from an old radio broadcast console.

Now, when a question is posed, the salesman can buzz in to answer, knowing that only the quickest person’s button click will be registered. When it’s time for another question, the host simply clicks his buzzer to reset the console.

While it’s not quite as fancy as this game buzzer system we featured a while back, [Chuck] says it does the job perfectly and was cheap to boot.

Continue reading to see a short video of the office game buzzer system in action.

This coffee table is a real show-piece. It’s got a smoky glass surface that is hiding the LCD screen within. But what fun would it be if it could only play video? The rest of the enclosure houses all the parts necessary to make this living room centerpiece into a computer.

After the break you can see a video showing off each step of the build process. It starts by ridding the screen of its enclosure, and using what’s left to determine the size of the wood frame for the table. With the display firmly in place [Nate] sets to work position, mounting, and developing cooling solutions for the motherboard and the rest of the bits. He does nice work and ends up with a table that we’d be proud to feature in our homes.

Now he’s got a lot of computing power and a huge display, but isn’t something missing? How hard do you think it would be to add touch sensitive input to this? We’re wondering if the overlays used to make those Android touchscreens could be mounted on the underside of the glass? 

Build log photos:

Short demo:

[Thanks Mathew]

If you’re one of the hordes whose Xbox 360 died the fiery death associated with the RRoD you may be wondering what to do with that multi-hundred dollar door stop you’re left with. Why not salvage the parts for other uses? If you’ve ever wanted to use your wireless controller with a computer here’s a way to pull out the RF module and reuse it.

The concept is simple enough, there’s a daughter-board in the Xbox 360 which hosts the RF module for wireless controller connectivity. Once you extract it from the carcass of the beast, you just need to find a way to read and push the data to your computer. Any USB enabled microcontroller will do, in this case an Arduino nano was chosen for the task. A bit of level converting was necessary to interface with the device, but nothing too involved.

It sounds like at first there was an issue with syncing a controller with the hacked module, but as you can see in the clip after the break that problem has been solved.

[via Build Lounge]

What’s better than one amazingly acrobatic quadcopter? How about a swarm of acrobatic micro-quadcopters? It’s not a rhetorical question, but an experimental reality. A team at the University of Pennsylvania are showing off their latest round of hovering robots which can move in formation and alter their orientation as a swarm.

You may remember us salivating over the unbelievable stunts the team pulled off with a single ’copter back in 2010. That device needed a sophisticated camera installation to give provide feedback, and this uses the same framework. But we don’t that detracts from the achievement; it’s simply a future hurdle for the project.

The video after the break shows some of the stunts the slew of whirring devices are capable of. Watching them move as a grid, and even landing simultaneously, we can’t help but think of the Dog Pod Grid from Neal Stephenson’s book The Diamond Age. It was used as a protection system, keeping unwanted flying intruders out. Doesn’t sound so far-fetched any more, does it?

http://hackaday.com/2010/05/28/quadcopter-acrobatics-like-nothing-weve-seen/