Making images and videos using a diy fluoroscopic x-ray

[Jozef] has been playing around with X-rays. Specifically, he’s been using his own setup to make fluoroscopic images, a type of x-ray photography that allows for video images to be made. If you’ve ever seen those x-ray movies of someone swallowing, that’s fluoroscopy (we’re fans of the other oddities like this video of a skeleton playing the trumpet).

The image above is [Jozef's] own hand. He exposed it for about one second, filming the event from the opposite side of a Curix Ortho Regular Screen. The screen fluoresces when hit by the particles from an x-ray tube he picked up on eBay. This particular event dosed his hand with about 10 rads. We have no clue as to what levels are safe (and a quick search didn’t enlighten us) so talk amongst yourselves in the comments section.

Of course [Jozef] didn’t stop with still images, he put a turntable between the tube and the screen and took a bunch of x-ray videos of revolving electronics. You’ll find the video embedded after the break.

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Playing video on an 8-bit microcontroller

The LCD displays for Nokia phones have seen a ton of use as easily interfaced displays for Arduino or other microcontroller projects. Usually, these LCDs are only used for displaying a few lines of text, or if someone is feeling really fancy, a small graph. Shame, then that we don’t see more complicated and computationally difficult tasks like playing video very often. [Vinod] sent us his way of playing video on these small color screens, surprisingly using only an ATMega32 microprocessor.

The build started off by saving uncompressed image data on an SD card using code from a previous project. [Vinod] was able to write a slideshow program to go through the SD card one file at a time and displaying each image. From there, it was simply a matter of using a Python script to convert frames of an .AVI video file to an uncompressed image and display them at 15 frames/second.

Turning these videos into talkies was a bit of a problem, but after taking an uncompressed .WAV file and sending that to a PWM pin on the ATMega, [Vinod] managed to play sound alongside his video.

The result is the ability to play a video with sound at 15 frames a second and a 132 x 65 resolution. You can check out the demo video after the break.

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Pimp my scooter

[Glen] built this shiny party machine out of a pretty sad-looking scooter. We’d bet you’re wondering why we think it’s a party machine when it looks so common? The only real giveaway in this photo is the custom exhaust, but hidden in the body of the beast is 720 Watts of party power plus a whole bunch of extras.

When he gets where he’s going, [Glen] parks his ride and lifts up the seat to unfold the entertainment. Attached to the underside of the saddle is a 720 Watt audio amplifier. It drives one big speaker under the seat, as well as two tweeters and two mid-range speakers that were fitted into the front console. But these days a party isn’t a party without some video, and that’s why you’ll also find a 7-inch LCD screen suspended from the upright seat. Tunes and videos are supplied by an iPod touch up front, or the PC he built into the ride. All it’s missing is a gaming console!

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Creating a multimedia elevator ride

[Ben Peoples] works in theatrical electronics. Sounds like fun, and here’s an example of the kind of stuff he does. We’re not sure what event this installation was used for, but if the elevator ride needed something flashy just think of what the party room must have looked like. These HDTV screens on the ceiling of the elevator play different clips when the elevator is moving up or down. The challenge for [Ben] was to find a way to make it work without tapping into the elevator electronics or requiring any button presses.

The first attempt at sensing the elevator’s travel was done with an accelerometer. The problem with this approach is that an accelerometer only senses change in acceleration and this method proved to be fairly error prone. [Ben] switched over to a reflective sensor which performed quite well. Since most of these sensors will only work within about an eighth of an inch he ended up building his own with a LDR and a couple of amber LEDs.

[via Reddit]

Projector calibration on uneven surfaces made easy


If you are thinking of building your own flight/racing sim setup at home, you might want to check this out. [Alex] from the Garoa Hackerspace in Säo Paulo, Brazil put together a slick setup that makes projector image calibration a breeze.

When building a wraparound screen for such a simulator, you are likely to run into problems with both overlapping images and distortion from the curved projection. There are projectors that can easily adjust themselves to work in this sort of setup, but they are often very expensive, so [Alex] thought he would build a solution himself.

After studying a paper written by [Johnny Chung Lee] in 2004, he built a prototype display calibrator last year that used similar, though slightly tweaked methods to get the job done. This time around, [Alex] has improved his calibrator, making the process more precise and a bit quicker.

Light sensors and an Arduino are attached to the back of the projection medium, and a large broad scan of the screen is performed by the projector. His code then triggers an additional sweep of each corner to better estimate the exact edges of his projection surface. Since the video is tweaked in software rather than relying on the projector hardware to handle the task, the result is cheap and very accurate.

Don’t take our word for it though, check out [Alex’s] video demonstration below to see his calibrator in action.

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Hackaday Links: December 16, 2011

Free-form Christmas ornament

Here’s [Rob]‘s free form circuit that’s a Christmas ornament for geeks. It looks great, but sadly isn’t powered through a Christmas light strand. It’s just as cool as the skeletal Arduino we saw.

Prototyping with flowers

Well this is interesting: protoboard that’s specifically made to make SMD soldering easier. The guys at elecfreaks went through a lot of design iterations to make sure it works.

We’ll call it Buzz Beer

The days are getting longer and cabin fever will soon set in. Why not brew beer in your coffee maker? It’s an oldie but a goodie.

Christmas oscilloscope

With just an ATtiny and a little bit of  futzing around changing the coefficients of a partial differential equation, you too can have your very own oscilloscope Christmas tree. Don’t worry though, there are instructions on how to implement it with an Arduino as well. HaD’s own [Kevin] might be the one to beat, though.

So what exactly does a grip do?

You know what your home movies need? A camera crane, of course. You’ll be able to get some neat panning action going on, and maybe some shots you couldn’t do otherwise. Want a demo? Ok, here’s a guy on a unicycle.

Video display from RGB strips makes it seem so easy

[Fabien] wrote in to share a link to this RGB video display which he made. He’s got some pretty cool routines that make it more functional than you would think, but first we want to comment on the construction. He used an RGB strip, which makes this look like an incredibly simple build. The strip has a data and power bus running the length of it. You can it into smaller segments, then just solder jumper wires to reconnect the buses. That’s exactly what he did here, making it what must be the fastest method of putting together a display of this size (16×10 pixels).

It’s driven by a Netduino which easily addresses the LPD8806 drivers responsible for the LEDs. It gets input from a computer via Xbee, making it easy to include data from the net, or to push visualizations. The video after the break shows a [Van Gogh] self-portrait. Since 160 pixel resolution wouldn’t do it justice, the visualization software shows a zoomed in portion of the painting which is constantly panning to let you see the entire work. It’s a fabulous effect.

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