Paintball Graffitti

Paintball as a large format printer? That’s exactly what facade printer is. A paintball gun was mounted with two controllable axes of movement. A computer reads in the image data and prints it out by shooting paintballs to form a dot-matrix display. There’s a couple of wins here, the paintball paint can be washed off, and this will work on coarse or uneven display medium. Check out a video of the printing process after the break.

If you already built your own paintball turret, give the other guys and chance and hack it to print instead of gunning down unsuspecting adversaries.

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Laser Command Game Uses Laser For Control

[vimeo=http://vimeo.com/10819322]

[Eliji Hayashi’s] project for a class at Carnegie Mellon University is absolutely delightful! It is a game he calls Laser Command because a laser pointer is used as the gaming controller. An 8×8 LED matrix serves as the display, but is also used as an 8×8 light sensor, much the same way as the LED advent project did. The display is rapidly switched between producing light and sensing it. The laser is bright enough that it becomes easy to pick up the voltage generated within the matrix during the sensing periods. The game is programmed on an Arduino mini and the whole thing wraps up into an incredibly small package. Brilliant.

[Thanks Juan]

Print Toner Directly To A PCB

We use the toner transfer method to fabricate printed circuit boards. The most difficult part of this is printing, ironing, and removing the paper from the toner that is used as an etchant resist material. [Mark Lerman] is developing a method to apply toner directly to the copper clad using a laser printer. Each of the photos in his gallery have comments that take us through his process. A laser printer has been modified to negatively charge the copper plate, thereby attracting the positively charged toner to it. Once the toner has been applied, the board is baked in an oven, then run through a laminator. This process can yield 2 mil traces and it looks like the potential for incredibly clean boards is just around the corner. The question is, will this be easier and take less time than using photo resist?

We’ve contacted [Mark] in hopes of getting more details. If you can’t wait for a follow-up, take a look at this thread concerning his work.

[Thanks Komradbob]

EMG Controlled Prosthesis

This prosthetic arm is the result of a student project. [Amnon Demri] and his classmates built it with below-the-elbow amputees in mind. It uses electromyography to actuate the fingers and wrist. Four stick-on sensors are placed around the elbow to sense electrical activity there. These signals are interpreted by a PIC 16f877a microcontroller which then controls the servo motors to operate the prosthetic limb. This sounds like a very economical solution and as you can see in the videos after the break, it works fairly well.

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IPhone 3.1.3 Unteathered Jailbreak

A method to Jailbreak the new 3.1.3 iPhone rom is here and it does away with tethering. Tethering is the problem that arose from the blackra1n exploit requiring a computer to reboot the iPhone. Although we saw a hardware workaround for that, it’s much nicer to do away with the issue completely. The new exploit is called Spirit and we found the site was getting hammered earlier so you should check out the writeup over at Redmond Pie if you can’t get through with the link at the top.

[Thanks Xb0xGuru via iPhone Hacks]

Wyvern quadcopter

[William Etter] and his classmates built a quadcopter as a class project. We love the details of these builds and they came through with some thorough documentation. Some highlights that we enjoyed were reading about ABS body design and construction, their analysis of two versus three blade propellers, and their breadboarded control mechanism. You can see their success in the most recent post, but we all know that trial and error plays a role in these builds so we’re glad they’ve shared a collection of crashes with us.

Can’t get enough of this four-rotor action? Check out this project of a similar design.

Remote Control Reel Mower

Challenged by hot days and steep turf [Grayson Sigler] modified his reel mower to use electric motors. The end product will be radio controlled but he lacked the necessary parts to make it wireless right now. Not to be deterred, he used a wired controller for prototyping and testing that should be easily replaced once the parts arrive. Sadly, the grade of his yard causes the small wheels to slip so he tried inserting screws into the tread for added traction. The small mower lacks the weight and footprint that the Lawnbot400 enjoys. That being said, solar charging is one of the future goals so this build, which he named RoMOW, wins out on the green scale. We’ve included the prototype video after the break that shows the blades spinning away.

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