We can think of no better way to describe this laser projector project than Epic. [C4r0] is a student at Gdansk University of Technology and he’s been working on this projector for at least a couple of years. It uses several different laser diodes pulled out of DVD burners, Blu-Ray drives, and entertainment equipment (the green diode is from a disco laser).

In order to direct the beams he built a series of brackets that hold dichroic filters which reflect some wavelengths of light while allowing others to pass straight through. Each diode also needs a driver, most of which he built from scratch. And once the hardware has been designed and tested, what does one do with it? If you’re [C4r0] you build it into a money case with professional-looking results.

Don’t miss the video demo after the break. And make sure you have a rag ready to wipe up the drool before you look at his forum post linked above.

[Thanks Kodex]

A while back, [Ben Gilstad] built his first HTPC, loading XBMC on it to manage all of his digital media. He loved XBMC’s features and flexibility, but he needed a way to enjoy his DVD and Blu Ray collection on the device without too much hassle. Far before [Ben Heck] considered fitting his Xbox 360 DVD drive into a CD carousel, this [Ben] was busy hacking a Blu Ray player into his.

He bought a broken disc changer at a garage sale, and tore apart a standard SATA Blu Ray player in preparation for the optical drive transplant. An ATMega168 controls the changer’s mechanics, monitoring the carousel’s position and triggering the proper motors when discs need to be swapped out. The AVR currently takes its direction from the HTPC over its serial port via a UDP proxy as XBMC did not support a serial interface at the time he was building the changer.

The second half of [Ben’s] project is an XBMC add-on that he uses to manage his huge collection of optical discs. In order to get XBMC to recognize each disc as a valid ‘file’, he created a clever workaround involving blank WMV clips. This enables him to view his DVDs as if they were digital files on his hard drive, complete with cover art.

It’s a fantastic project, and [Ben] says that his system should be able to support any number of physical disc changers simultaneously, without much issue. Unfortunately the project went on hiatus when he lost his job, so it’s packed away in storage for the time being. Once he gets back on his feet however, he has a whole list of planned changes and improvements to work on – we can’t wait to see it once complete!

Keep reading to check out a video demonstration of his XBMC add-on in action.

This laser display is persistent thanks to a glow-in-the-dark screen. [Daniel] built it using a Blu-ray laser diode. As the laser dot traverses the screen, it charges the phosphors in the glow material, which stay charged long enough to show a full image.

The laser head is simple enough, two servo motors allow for X and Y axis control. A Micro Maestro 6-channel USB servo controller from Pololu drives the motors, and switches the diode on and off. This board offers .NET control, which [Daniel] uses to feed the graphics data to the unit. Check out the video demonstration below the fold to see a few different images being plotted. It’s shot using a night-vision camera so that you can really see where the laser dot is on the display. It takes time to charge the glow material so speeding up the plotting process could actually reduce the persistent image quality.

This is yet another project that makes you use those geometry and trigonometry skills.

[Jo0ngle] wanted a fun toy and an easy conversation piece. He painted a square on the back of his door with some glow-in-the-dark paint. Now he can draw on it using a blu-ray laser or a UV flashlight. Either way, the effect is quite pleasing. [Thanks Justin]

Resistor decoder rings

This resistor reference card allows you to spin a wheel and dial in the resistor color code for easy reading. We know, you have the simple act of reading resistor code down cold by now. This is still a fun idea that you might use if you’re ever helping someone get into electronics. [Thanks Osgeld]

Resistor bending template

Speaking of resistors, [Jerome] helped us out by designing a resistor bending template. He’s actually marketing himself at the same time. His bending template is folded from one of his business cards, which he came up with after being inspired by some of the unique business cards we’ve covered in the past.

Fake stained glass using old PCBs

[Agg] floated some old PCBs to his friend [Dan] the mason. [Dan] proceeded to turn out an amazing looking stained glass window unit using the colorful leftovers. The picture above doesn’t do it justice, you have to click through to see the real art.

Monovelo monowheel

[Ernst] asked if we’d heard of the Monovelo monowheel. Well we hadn’t. It’s a human-powered vehicle where you sit inside of one large wheel. We don’t see ourselves building one or riding one, but we enjoyed watching someone else do so. We’d like to catch somebody commuting to work with one of these. Seeing this in the bike lane will brighten up anyone’s day.

Here’s another Star Trek phaser toy with a laser added. [Jay] started with a 1994 Star Trek phaser and added a 12X Blu-Ray diode. The sound effects of the toy still work, a nice touch that you can check out in the video after the break. That video shows him popping balloons with the laser, a feat made possible by the 465 mW that it puts out when the diode is driven at 320 mA of current. He’s made a nice carrying case for the weapon but we didn’t see a spot in there for protective glasses like we’ve seen with other phaser hacks. He did make one safety consideration by adding a safety switch and indicator LED to signal when the laser diode is armed.

Phasers come with two settings: stun and kill. [Luke] took this seriously when he put two Blu-ray lasers into a toy raygun. He picked up the toy from Amazon for about twenty bucks and set to work.

The laser diodes are both pulled out of a 6x BD-R burner, which we think is a pretty expensive source to scavenge from. [Luke] removed the toy circuitry, reusing the trigger, top switch, and battery pack. The two diodes are mounted on a swiveling carriage which is turned 180 degrees to switch between the two diodes. A boost driver converts the 3v from the batteries up to 7v for the diodes.

This is a skillful conversion and [Luke] should be proud. Don’t miss the video after the break and if you’re thirsty for more take a look at the last hand held laser we featured.

Last month we had the pleasure of bringing you [FireMyLaser's] green laser spirograph. Just green is great for a while, but why not add red and blue for a full spectrum of color! [c4r0] steps in at this point to bring us his red green blue laser. He dug around inside Blu-ray players and DVD drives until he had a collection of lasers, refractors, and other filters that fit his needs. With some careful toothpick alignment and glue, his setup was complete.

But then he went further by modified his galvo scanner to accept the RGB laser; requiring a custom circuit board and new software, both available on his site. The original is in Polish, but Google does a decent translation. Check after the jump for a video.

[Jay] hacked a Blu-Ray laser diode into a keychain enclosure. He found a heavy brass keychain light from Lowe’s and stuffed the diode and a larger battery inside. The existing batteries weren’t powerful enough, so he drilled out the endcap to fit a 200mAh 3.6v lithium battery inside. He also modded the power button to only momentarily turn on the diode. With the larger battery, the laser can run for about an hour between charges. In addition to a Blu-Ray lasers, he also has versions with a 200mW red diode.

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