Giant Pencil Used As An Etch A Sketch Stylus

The gang over at Waterloo Labs decided to add a team-building aspect to a plain old Etch a Sketch. Instead of just twisting the two knobs with your own mitts, they’re converting this giant pencil’s movements into Etch a Sketch art.

The challenge here is figuring out a reliable way to track the tip of the pencil as it moves through the air. You may have already guess that they are using a Microsoft Kinect depth camera for this task. The Windows SDK for the device actually has a wrapper that helps it to play nicely with LabView, where the data is converted to position commands for the display.

On the Etch a Sketch side of things they’ve chosen the time-tested technique of adding gears and stepper motors to each of the toy’s knobs. As you can see from the video after the break, the results are mixed. We’d say from the CNC ‘W’ demo that is shown there’s room for improvement when it comes to the motor driver. We can’t really tell if the Kinect data translation is working as intended or not. But we say load it up and bring to a conference. We’re sure it’ll attract a lot of attention just like this giant version did.

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Toy Helicopter Charging Fix

[Onefivefour] was surprised that his E-flite Blade MCX radio controlled helicopter came with a charger that used AA batteries to recharge the lithium batteries in the flying unit. Yeah, that’s a bit crazy. He set out to modify the base unit to work with AC power. There are four batteries inside this base unit, one of them powers the charge detector circuit and the others are used to juice-up the chopper’s rechargeable cells. He took a 5V regulated charger from a Motorola cellphone and modified it to interface with the contacts for the three AA cells. Like the Magic Trackpad hack, he did this without altering the holder by cutting a couple of pencils to length and attaching the positive and negative contacts from the AC charger to them. Check out the video after the break for a walk though, noting how he still has the option to go back to battery power if he so chooses.

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Pencil Balancer A Bit Noisy For Desk Use

Who wouldn’t want to install this little bot as your newest pencil holder? Place a pencil tip-down and it will keep it from falling using two motors. There is a Dynamic Vision Sensor for each axis that provides feedback, but it’s not the same as using a camera. These sensors pick up changes in pixel contrast, outputting a positive or negative number based on the direction the pencil is beginning to fall. An NXP2103 running at 64 MHz reads in the values and drives the pair of servo motors accordingly.

If you’re interested in the nitty-gritty the full paper is available from the page linked above. It goes into great detail about the algorithm used, and includes plots and histograms showing the data capture during a balancing session. Or you can skip the eggheaded exercises and watch the video after the break.

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Paper Touchpad

If you don’t mind getting your fingers a little dirty you can replace your mouse with a piece of paper. [Dr. West] made this touchpad himself, which measures signals at the corners of the paper using four voltage dividers. The paper has been completely covered with graphite from a pencil (which we see in hacks from time to time), making it conductive. The user wears an anti-static strap that grounds their hand, allowing an Arduino to calculate contact points on two axes when a finger completes the circuit. See this controlling a cursor in the video after the break.

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Solderless Drawdio Terminally Implemented

So you’re stuck in a boring class and you can’t fight off the urge to hack something, even your pencil, to pass the time. Maybe you are performing a live electronics show and you drop your synth down a flight of stairs and all that you are left with is a handful of components, a screw terminal block and a pencil. There are thousands, perhaps millions of these kinds of situations and for each one the answer is the solderless drawdio clone by [Martin].

You may have seen the original Drawdio here before, a fun piece of technology that is simple enough to recreate. This latest approach would make an excellent introductory project for a hacking workshop seeing as the guide is straightforward and the lack of soldering would make logistics so much easier. The results are very similar to the original–check the video after the break. Continue reading “Solderless Drawdio Terminally Implemented”

Personal Pencil Production Plant

[vimeo=http://vimeo.com/9661763]

[Robb Godshaw] put together a pencil production line for home use. The whimsical assembly line starts with a graphite rod and extrudes clay polymer around it. From there it’s down a conveyor belt to get stamped and then into the oven made from a hacked toaster. The final step is to cut out a plug of eraser and attach it to the back-end of the pencil. This low-speed assembly line reminds us of a Rube Goldberg machine with all the wasteful steps cut out.

Better Resistors From A Pencil

Many of us here in the office (myself included) can’t tell the difference, but the audiophiles out there who want the best sound from their resistors should check out [Troel’s] write-up for making your own non-inductive graphite resistors. Graphite resistors have the traits for being non-inductive, have a negative temperature coefficient, and supposedly sound better. We liked the detail of his tutorial and how he gives many examples for making your own graphite resistor.

[Thanks Maxime]