If you are considering repurposing some old computer equipment to create music, be aware that the bar has been raised just a tad. YouTube user [BD594] spent some time sifting through his bin of used electronics and put together a 5-piece band that plays a pretty awesome rendition of The Animals’ “House of the Rising Sun”.

Last week, we saw a pretty impressive hack with a floppy drive that could bang out music using a calculator, but this takes things to a whole new level. [BD594] used an old HP ScanJet to simulate the song’s vocals, while an Atari 800XL combined with an oscilloscope is used as an organ. A Ti-99/4a is used in conjunction with another scope to play guitar notes, while a PIC-controlled hard drive does double duty, playing both the bass drum and cymbals.

We dare you to watch the video below and NOT be thoroughly impressed with his work.

[BD594] says that once he has a bit of free time, he’ll be putting out another video – something we’ll be anxiously waiting to see.

Some projects benefit greatly from the parts a builder is able to find. Take this UV exposure bed for photo-resist copper clad boards (translated). It looks like a commercial product, but was actually built by [TabascoEye] and his fellow hackers.

The main sources for parts were a flatbed scanner (which acts as the case) and two self-tanning lamps that use UVA flourescent bulbs. By sheer luck the bulbs and their reflectors are exactly the right size to fit into the top and bottom cavities of the scanner. The control hardware centers around an ATtiny2313 micorocontroller, which takes input from a clickable rotary encoder, and displays exposure information on a character LCD. The finished product deserves a place right next to other professional-looking exposure boxes that we’ve looked at.

The Gado project is part of the Johns Hopkins University Center for African Studies. It has been tasked with archiving documents having to do with the East Baltimore Oral Histories Project. In short, they’ve got a pile of old pictures and documents that they want digitized but are not easily run through a page-fed scanner because they are fragile and not standard sizes. The rig seen above is an automated scanner which picks up a document from the black bin on the left, places it on the flat-bed scanner seen in the middle, and moves it to the black bin on the right once it has been scanned. It’s not fast, but it’s a cheap build (great if you’ve got a tight budgt) and it seems to work.

The machine is basically a three-axis CNC assembly. Above you can see one motor which lifts the lid of the scanner. You can’t see the document gripper in this image, but check the video after the break which shows the machine in action. A vacuum powered suction cup moves on a gantry (y-axis) but is also able to adjust its height (z-axis) and distance perpendicular to the gantry (x-axis) in order to grab one page at a time.

The pictures on the build log have captions to give you an idea of how this was built. We didn’t see any info about post-processing but let’s hope they have an auto-crop and auto-deskew filter in place to really make this automatic.

For their senior ECE 4760 project, engineering students [Brian Harding and Cat Jubinski] put together a pretty impressive portable face recognition system called FaceAccess. The system relies on the eigenface method to help distinguish one user from another, a process that the pair carried out using MatLab.

They say that the system only needs to be hooked up to a computer once, during the training period. It is during this period that faces are scanned and processed in MatLab to create the eigenface set, which is then uploaded to the scanner.

Once programmed, the scanner operates independently of the computer, powered by its own ATmega644 micro controller. Users enroll their face by pressing one button on the system, storing their identity as a combination of eigenfaces in the onboard flash chip. Once an individual has been enrolled, a second button can be pressed to gain access to whatever resources the face recognition system is protecting.

The students say that their system is accurate 88% of the time, with zero false positives – that’s pretty impressive considering the system’s portability and cost.

Stick around to see a quick demo video of their FaceAccess system in action.

[Csshop] is setting a new bar for building an inexpensive CNC mill. Not only did he complete his build at a very low cost, but it seems to work quite well too. Check out the video after the break to see the device cut out thin wood parts for a toy plane.

The majority of the build uses scrap wood for the body of the mill. The business end of the device is a flexible rotary attachment for a Dremel tool which takes a lot of the weight and bulk out of the gantry assembly. Old flat bed scanners were gutted for the precision ground rod and bearings, as well as the three stepper motors used to drive the axes. An Arduino board controls the device, commanding the stepper motors via EasyDriver boards.

Once the hardware is assembled there’s still a fair amount of work to do. [Csshop] builds his designs in Google Sketchup, but some conversion is necessary to arrive at code that the Arduino will understand. He’s got a second project write-up that covers the software side of things.

[Sprite_TM] was cleaning up his hacking workbench when he came across an all-in-one device that had seen better days. After a bit of consideration he decided to tear down the scanner portion of the device and ended up turning it into a multi-touch display.

The scanner relies on a long PCB with a line CCD sensor. This sensor is read in a similar way that information is passed along a shift register. Tell it to take a reading, and then start a clock signal to pulse out each analog value from the pixels of the sensor. In order to scan color images it uses multicolored LEDs to take different readings under different illumination.

[Sprite_TM] takes advantage of this functionality to turn it into a multitouch sensor. The sensor board itself is mounted below an LCD display along with a shield with a slit in it to help filter out ambient light. Above the screen a series of LEDs shine down on the sensor. When you break the beams with your finger it casts a series of shadows which are picked up by the sensor and processed in software. Watch the clip after the break to see it for yourself. It has no problem detecting and tracking multiple contact points.

Here’s a simple and interesting idea that increases the visual persistence of a laser scanner image. Using glow-in-the-dark paint, [Daito Manabe] prepares a surface so that the intense light of a laser leaves a trace that fades slowly over time. He’s using the idea to print monochromatic images onto the treated surface, starting with the darkest areas and ending with the lightest. The effect is quite interesting, as the image starts out seeming quite abstract but reveals its self with more detail over time.

As evidenced in the test videos, the bursts of laser scanning are matched to the fade rate of the paint. Therefore it would seem that the time taken to “write” an image is directly proportional to the desired visual persistence of the final image. We wonder, by combining clever timing and variable laser intensity could you write images much more quickly? How hard would it be to use this for moving pictures? With the ability to create your own tiny laser projector, and even an RGB scanner, there must be a lot of potential in this idea for mind-blowing visual effects. Add portability by using a phosphor-treated projection screen!

Share your ideas and check out the test videos after the break.

Playing store just got really, really fun because you can now build your own LEGO barcode scanner. As you can see after the break, it works well and it’s fast like a real barcode scanner. Unfortunately it doesn’t scan real barcodes. Or at least not traditional ones. As we learned in the Barcode Challenge, standard barcodes are a set of white and black bars that make up the ones and zeros of the code. This system uses the same white and gray bar system but it seems that it’s only the number of bars that identify an item, not a code created by a particular combination of light and dark. The items above are all scannable because the scanner counts the 2, 3, 4, 5 or 6 white beams on the bottom of each package. Still, it’s incredibly clever and a great toy for the young hackers to build if they have a little help.

[via Tinkernology]

These greeting cards must be the product of a mechanical engineer run amok. They come with a crank and are designed to entertain with their simple, yet elegant movements. [Thanks Phil]

Magnetic card stripe reader

[JP] built an Arduino based magnetic card reader. It uses off-the-shelf parts but if you don’t mind buying the components this will get you up and running in no time. If you want more info there’s also this Teensy based version.

Homemade Airsoft sentry gun

This sentry gun has an amazingly fast firing rate that can continue for quite a while, thanks to the big flashlight housing that is holds a lot of ammo. [Thanks David]

Scanner easter egg

The engineers over at HP had a little fun building an easter egg into this scanner. If you know what you’re doing you can get it to play the Ode to Joy. It needs to join the old-hardware band from our Links post earlier in the month. [Thanks Googfan]

[Greg] sent in his biometric pistol safe lock. He keeps his guide light on details so not every Joe can crack the system (there is a thread to sift through if you really wanted to), but the idea runs fairly simple anyway. [Greg] took an old garage door opening fingerprint scanner and wired it into a half broken keypad based pistol safe. While he did have some issues finding a signal that only fired when the correct fingerprint is scanned, a little magic with a CMOS HEX inverter fixed that problem quick.

This does bring one question to our minds, are fingerprint scanners as easy to crack as fingerprint readers?

Find yourself an old record player, a laser level, and a digital scanner and you can build a 3D scanner. That’s what [Rob] did. The camera and laser level are mounted on the turntable for steady rotation. The camera captures the vertical laser line traveling around the room by recording 30 fps at a resolution of 640×480. This data is then translated into a Blender 3D file via a Python script and the Python Image Library. You can scan a whole room or just a small object. The face above is the result of this image capture after a bit of processing. [Rob] found this worked best in the dark and when scanning surfaces that are not reflective.

Make sure you also check out the camera-and-projector scanning method.

[Kyle McDonald] has kept himself busy working on 3D scanning in realtime. He’s posted a writeup that takes us through the concepts, tools, and assembly of a DIY 3d scanning camera. You should remember a preview of this method posted earlier this month, but now it’s time to build your own. You’ll need a camera, a projector, and some open source software to process the image data. Using these simple tools, [Kyle] turned out much better video than before. Take a look after the break to see his results from scanning at 60 fps using a PS3 Eye. The trick to this setup is getting the correct synchronization between the projector and the camera, something that could be improved with a bit of extra hacking.

Does [Kyle's] name sound familiar? It should, he’s got a long history of quality hacks that we’ve featured over the years. If you’re looking to use a scanner as a multitouch, add some music to tea time, or play with your skittles his work will give you a shove in the right direction.

[Photodesaster] put together a panoramic digital camera using a scanner and some miscellaneous parts. You may remember seeing something like this about six months ago and originally about five years back. The parts used here work together nicely. The sensor board from the scanner is mounted to a metal plate along with a 50mm lens. The plate is mounted to a hard drive platter that is turned via belts connected to the original scanner motor. This way, when you tell the computer to scan an image, the lens is rotated to capture the panorama. The use of an 18V tool battery is a nice portability hack for the scanner circuitry.

Judging from this 71MP image he has achieved some remarkable results.

[Thanks Stefan]

Here’s a good one from a few years back. [Muranushi] built a scanner to automatically scan an entire book. LEGO is used as the primary building material. A book is placed on a LEGO balance (inset photo) with a counterweight that eases the work of raising and lower the book. The book is lowered, a LEGO carriage moves across the book to turn the page, the book is raised to the glass of an upside-down scanner and scanned into a laptop.

It seems LEGO and imaging devices are a great match. Most of the parts used here are from LEGO Technical set 8485, a set that comes with motors and a motor controller seen above, on the floor behind the computer. We’ve embedded some video after the break of a book in the midst of the scanning process.

[Thanks Vesanies]

Remember slide shows? The ones that used a carousel projector and real slides? [Brian] wanted to bring his slides into the digital age but was spending far too much time scanning in the 35mm relics. He set to work and built a rapid slide digitizer using a projector, a DSLR, and a microcontroller.

His system centers around an AVR microprocessor, the ATtiny2313. Some DIP switches are used to set the number of slides to be scanned, and the timing for synchronizing the projector and the camera. Using two relays, the cable release for the DSLR and the remote advance pins on the slide projector are connected to the AVR. [Brian] used a macro lens and sets the focus, exposure, and f-stop manual. Once everything looks good the touch of a button quickly steps through the entire carousel at about 1 slide per second. A small video of the process is embedded after the break and his writeup has some comparison photos between a slide scanner and this setup.