Bill Hammack Explains How LED Backlit LCD Monitors Work

March 17, 2011 by Mike Szczys 14 Comments

We had a basic understanding of how LCD monitors worked, and you may too. But the thing is, [Bill Hammack] doesn’t just explain the basics. Since he’s the Engineer Guy he explains the engineering principles behind how LED backlit LCD screens operate. But he does it in a way that everyone can understand.

After the break we’ve embedded his five-minute video. In it you’ll see him strip down a monitor to the back plate and then build it up piece-by-piece. We enjoyed his discussion of how the diffuser panels work together to even out and distribute the light. Theses are made of several layers and, although we knew they were there from working with salvaged LCD screens, we never knew quite what they were doing. He also covers how each liquid crystal cell works along with polarizing sheets to either block or allow light passage. And he’ll bring it on home by show how thin-film transistors in each subpixel of the screen work to multiplex the display, just like we did with that pumpkin back in October.

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AV Test Box Meets The Incredible Shrink Ray

March 17, 2011 by Mike Nathan 7 Comments

mini_avtester

[Chris] recently finished building a miniscule AV Test Box, capable of fitting inside a standard Altoids tin. It is a revision of a project he constructed a few years ago. His previous test box worked well, but was large and cumbersome – definitely not something you would want to carry around from place to place with any frequency.

The new test box does everything its predecessor is capable of, which includes displaying an 800×600 VGA test pattern as well as generating sound signals for testing audio systems. He updated the circuit design a bit, employing a newer PIC processor to run the show, otherwise most of the design details have remained the same, form factor aside.

His build log is full to the brim with details as usual. You will find thorough descriptions of all the components he used, schematics, source code, as well as the theory behind the build.

Be sure to check out the video embedded below of his new AV tester in action.

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Commandeering Public Video Screens: Real Or Fake?

March 14, 2011 by Mike Szczys 66 Comments

It’s time for everyone’s favorite comment thread game: Real or Fake? This week’s edition comes in from a tip that [Phil] sent about a way to take over video screens in Times Square. Watch the video after the break to see the hackers using a two-part solution to rebroadcast video from an iPhone onto a screen in the busy urban setting. The first part is a transmitter that plugs into the iPhone, the second is a signal repeater that, when held close to a video screen, overrides the clip currently being displayed with the video from the handheld. The image above shows the repeater being floated up to the big screen using a giant red balloon which you can make out in the black bar to the left of the replayed video.

Our first thought is that someone just watched Tron: Legacy and wanted to have a little Sci-Fi fun with the Internets. We can’t imagine a hardware solution that would actually make this work, but please do share your thoughts about that in the comments. We’d suspect this is more of a video hack that uses After Effects, similar to how the stopped motion candle video of the eyelid shutter glasses videos were faked. But apparently there is a follow-up video on the way that will show how the prototype was made so we could be wrong.

update: [Phil Burgess] points out that the “repeater” looks awfully familiar.

Fake for a variety of already-stated reasons (e.g. video out the headphone jack?). But the smoking gun, watching the 720P video on YouTube, is that I plainly recognize the hardware they’re using as the “repeater”: it’s simply the internals from a Digipower JS1-V3 cell phone USB boost charger (having torn apart a few myself):

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Hackerspace Camera Rig Auto-alerts The Internets When Projects Are Finished

March 10, 2011 by Mike Nathan 5 Comments

alerttheinternets_cam

It seems like every hackerspace has their own means of communicating status messages to their members. The hackers at [MetaLab] in Vienna have put together a rather novel way (Google translation) of letting the world know they have completed a project. While some hackerspaces simply notify their members that they are open for business, this hack takes things a step further.

When a project is deemed complete, the camera is removed from the dock, and any number of videos can be recorded. When the camera is returned to the dock, a canned introduction video is added to the recordings, then everything is automatically uploaded to YouTube. No extra time is required, no video editing needs to be done – their work hits the Internet immediately once they have finished filming it.

It’s a great idea, and something that every hackerspace should have. It would be even better to see these things installed in public areas to allow for immediate reporting of events as they occur.

If you are so inclined, be sure to check out [MetaLab’s] YouTube channel.

[via Make]

Giant Oscilloscope Music Display

February 28, 2011 by Mike Nathan 9 Comments

oscilloscope_wall

[Andrew] sent us a video of his home made oscilloscope wall, which he uses to visualize different audio tracks he has created. The wall is made up of nine old broadcast monitors he wired together in his studio. At first it appears that the monitors are split into two sets of four, with the center monitor running separately, but upon further inspection it looks as if he can control the display of each monitor independently.

We’re pretty sure he is not using an actual oscilloscope to generate the visuals, but rather visualization software that can approximate the output of an O-scope set in X-Y display mode. Though the screens run independently, it would be great to see all nine screens working in concert to display one large visualization. [Andrew] mentions that an high-def version is in the works, so perhaps we’ll see more features added in that iteration.

Stick around to watch a video of his oscilloscope wall in motion.

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Remote Phone Control Using Bluetooth And A Video Stream

February 27, 2011 by Mike Nathan 19 Comments

remote_bluetooth_phone_control

Hack-a-Day reader [Bobbie] sent us a hack that is an adaptation of the automatic cell phone button pushing machine we featured earlier this week. Inspired by that project, he challenged himself to construct a more efficient way to tackle the problem.

He started out in much the same fashion, pointing a camera at the phone in order to view the display remotely. The main thing he focused on to make his project unique was they way in which the buttons on the phone were activated. He was impressed by the mechanical button pressing rig, but thought it to be overly complicated. Instead, he decided to send button presses over Bluetooth to his phone which happened to be AT+CKPD compatible (PDF).

Not only that, his interface is quite impressive too. Originally planning to use the keyboard to send input to the phone, he changed course and programmed his video stream GUI to register mouse clicks instead. Now, when he clicks one of the phone’s buttons in the video display, the appropriate button press is sent to the phone – Awesome!

Keep reading to see a video of his remote phone interface, you’ll be glad you did.

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Video Projector From An Old Single-slide Unit

February 24, 2011 by Mike Szczys 21 Comments

Here’s a video projector that [Matt] hacked together. He needed a small and inexpensive solution to use with his R2D2 build. As you can see in the video after the break, it has no problem playing back the Princess’ distress call. But even if R2D2 is not one of the droids you’re looking for, we think this can be useful in other ways. One use that pops into mind is for projector-based Halloween displays.

As with past projector hacks, all you really need to pull this off is a light source, an LCD screen on which you can playback video, and a lens to focus the light onto a screen. Usually the LCD is the most expensive part of the project and building an enclosure to the correct dimensions can be a bit difficult. [Matt’s] solution was to use an MP4 knockoff media player. The rest of the setup is a ’50s era slide projector. The screen from the media player is about the same size as a single film slide, so he removed the screen from the case and put it where the slides go.

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