Over engineering windshield wipers to sync to music

In the late 90s, Volkswagen aired a series of awesome television advertisements that won a few awards relevant to those in advertising circles. One of these ads was titled Synchronicity and showed a VW Jetta’s windshield wipers (among other things) syncing to music as the car drove down a rainy alley. [ch00f] thought beat tracking wipers would make for a great project, and we love the sheer amount of engineering that went into this build.

The build began with [ch00f] taking apart his wiper motor to get some specifics for his build. Ideally, a rotary encoder would be very useful for this project, but designing a durable encoder would be a pain anyway. [ch00f] had to settle with the ‘parking pins’ on the wiper gear motor that allow the wipers to be driven in intermittent mode.

[ch00f] spent a great deal of time writing code that would guarantee a constant wiper speed, but that didn’t solve the problem of phase, or having the wipers begin or end their cycle on the beat. This problem was somewhat solved (as you can see in the video after the break) by using a feed forward system – basically, the software would predict the change in phase needed and correct it by changing the speed.

The build still isn’t perfect, although that’s mainly due to the placement of wiper parking switch on the wiper motor. [ch00f] plans on spending a little more time correcting the wiper speed/phase control with software, but what he’s got now is still very impressive.

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Hackday Links: March 10, 2012

We’re throwing money at our monitor and nothing’s happening!

Sometimes we get hacks sent into our tip line that are outrageously awesome, but apart from a YouTube video we’ve got nothing else to write about. So begins the story of the flying Back to the Future DeLorean quadrocopter. Sadly, the story ends with the video as well. (If you’ve got any info, send it in!)

Fine, we’ll throw in another cool car

Mercedes covered a car with LEDs and made the James Bond’s invisible car from Die Another DayThe Mercedes video cost tens of thousands of dollars to produce, so of course there’s camera trickery; we’re just wondering how much credit Adobe After Effects gets for this build.

Microsoft touchscreen demo might be impossible

Yes, Microsoft does care about user experience. Just take a look at this video from their applied sciences group. They did user testing with touchscreens that updated every 1 millisecond, compared to the ~100ms our phones and tablets usually update. Of course the result was a better UX, but now we’re wondering how they built a touch screen that updates every millisecond? That’s a refresh rate of 1 kHz, and we’ve got no clue how they bodged that one together. We’re probably dealing with a Microsoft Surface projector/IR camera thing here, but that doesn’t answer any questions.

Edit: [Philip Rowney] sent in a tip that it could be this TI touch screen controller that can sample above 1 kHz. The only problem is this chip uses a resistive touch screen, instead of a multitouch-enabled capacitive screen. At least that solves one problem.

And now for something that can measure 1 kHz

[Paleotechnologist] posted an excellent guide to the care and feeding of an oscilloscope. Most of our readers probably already know the ins and outs of their awesome Techtronix and HP units, but that doesn’t mean the younglings won’t have to learn sooner or later.

Good idea, except the part about saving it for spring

In a moment of serendipity, [Valentin] figured out how to use touchscreens with wool gloves. The answer: rub thermal grease into the tip of the index finger. It works, and doesn’t look to be too much of a mess. We’ll remember this for next winter.

The last one didn’t have a picture, so here’s this

[Darrell] used a little bit of LaTeX and Ruby to make colored labels for his resistor collection. We’re struck with the idea of using test tubes to organize resistors. It’s cool and makes everything look all sciencey and stuff.

Adding a laser sight to your drill press in just a few easy steps


[Derek] was using his Dremel drill press to prep a bunch of PCBs, and found that it was getting difficult to focus on the spinning drill bit each time to line it up with the solder pads on the boards. He figured that a laser sight would help move the process along, but since no off the shelf solution was available for his press, he built one of his own.

He bought a cheap desk lamp with a flexible metal neck, which he disassembled, saving the flexible metal sheath. He installed a conduit clamp on one end of the neck, and a laser module at the other. [Derek] then mounted the laser arm on the press’ crow’s nest aiming it at the tip of the drill bit.

As you can see in the video below, the ability to easily position the drill bit using the laser helps him make quick work of any PCB.

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3D printing from an Android device

[skullkey] over at the House4Hack hackerspace in Pretoria, South Africa wanted a way to get kids excited about technology and desktop fabrication labs. Wanting to give kids a visceral feel for the march of technology, he created Makerdroid, an android app that allows for the creation 3D objects on an Android tablet and preparing them to be printed on a Reprap or Makerbot.

What’s really interesting about this build is not only the fact that [skullkey] and his lovely beta testers are generating .STL files on an Android device, the object files are also being converted to GCode on the Android, without the need for a conventional computer. Makerdroid uses the very popular Skeinforge to generate the instructions for the printer (although a lot of people are switching over to Slic3r).

Makerdroid doesn’t need a PC to print objects out on a 3D printer, but we think the process of shuffling GCode files from a tablet to the printer with an SD card is a little archaic. It might be possible to print directly from an Android tablet over Bluetooth with the Android Bluetooth Reprap app that is currently in development. Still, we love the idea of printing objects we just created on a touch screen, as shown in the Makerdroid demo video after the break.

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Steganography in xkcd comics without the img alt tag

Inspired by a recent Hackaday post [austin] decided to try his hand at steganography. Steganography, or ‘concealed writing’ has come a long way from ancient Greek slaves/couriers shaving their head, tattooing a message on their scalp, and regrowing their hair. We recently saw a music file masquerading as a picture of a kitten, but that method of hiding data required running a Ruby script. [austin] thought steganography would be a great way to hone his JavaScript skills, so he made an image encoder and decoder purely in JS and HTML.

Like the previous incarnation, [austin]’s work takes a regular .PNG image file and hides stuff in the pixel data. A few of the lower bits for each pixel are modified (three bits from the red and blue, two bits from the green – a good choice, the human eye is very sensitive to green) and a file is embedded inside the .PNG image.

For an example, [austin] embedded some stuff inside the xkcd comic underneath this post’s title. Even though the image is mostly white, we can’t see anything wrong with the colors. If you’d like to decode the message, [austin] put his encoder and decoder up on github. Feel free to take a shot at it.