Beams of Light: An Oscilloscope Demo

beamsoflight

The demoscene is alive and well, with new demos coming out on a multitude of platforms, including oscilloscopes. Beams of Light is a new demo released at @party in Boston by [TRSi]. Beams isn’t the usual .EXE file format for PC based demos. It’s distributed as a 4 channel wave file. The rear left and right channels are stereo audio. The front channels, however, are vector video to be displayed on an oscilloscope in XY mode.

Beams of Light isn’t the first demo to use an oscilloscope. Youscope and Oscillofun preceded it. Still, you can see [TRSi] pushed the envelope a bit with his creation. He used Processing and Audacity to create the vector video, and his own line tracing algorithm to reduce flyback lines.

[TRSi] included an updated copy of a python based oscilloscope emulator so you can play the demo even if you don’t have the necessary hardware. We wanted to run this the right way, so we powered up our trusty Tektronix 465 and hooked it up to a 1/8″ stereo plug.

Sure enough, the demo played, and it was glorious. We did see a few more retrace lines than the video shows. This could be due to our scope having a higher bandwidth than the 10MHz scope used in the YouTube video. XY demos are one of those rare cases where an analog scope works much better than a low-cost digital scope. Trying the demo on our Rigol ds1052e didn’t yield very good results to say the least. Sometimes good old phosphor just beats an analog to digital converter.

[Read more...]

(Better) Full Motion Video On The First PC

Ladies

Ten years ago, [Trixter] created 8088 Corruption, a demo for the original PC, the IBM 5150, that displayed full motion video using a CGA card and a SoundBlaster. It was hailed as a marvel of the demoscene at the time, garnered tons of hits when it was eventually uploaded to Google Video, and was even picked up by the nascent Hackaday.Now, ten years later, and seven years after [Trixter] said full motion video using the graphics mode of a CGA adapter was impossible, he’s improved on his earlier work. Now, it’s possible to display video at 640×200 resolution at 30 frames per second on a 30-year-old computer.

[Trixter]‘s earlier work used the text mode of the CGA adapter, only because the 40×25 character, 16 color mode was the only graphics mode that could be entirely updated every single frame. It’s still one of the high points of the PC demoscene, but from the original video, it’s easy to see the limitations.

A while back, [Trixter] said displaying video using his computer’s graphics mode was impossible. He’s had years to think about this statement, and eventually realized he was wrong. Like the developers of modern video codecs, [Trixter] realized you don’t need to change every pixel for every frame: you only need to change the pixels that are different from frame to frame. Obvious, if you think about it, and all [Trixter] needed to do was encode the video in a format that would only change dissimilar pixels from frame to frame, and manage the disk and memory bandwidth.

After reencoding the 10-year-old demo for graphics mode, [Trixter] turned toward his most ambitious demo to date: playing the ‘Bad Apple’ animation on an 8088. As you can see in the video below, it was a complete success.

[Read more...]

Dual displays on a Playstation 2

scope

At the Revision 2013 demoparty held last weekend, visitors and guests wanting to check out the latest advances in programming old video game consoles got a real treat. [Abyss] took a Playstation 2, connected the composite video out port to a TV and an oscilloscope, and created the first dual display PS2.

From the official video of the demo, the two video signals are generated from a single video out on the PS2. Generating the composite video out is understandably fairly easy, but the second display – an oscilloscope – is driven during the Vblank period in the composite signal. There’s no audio trickery here; video signals are used for video, and audio signals are used for audio.

[Abyss] took first place in the wild demo competition at Revision 2013. Understandably, too, because this is one of the best demos we’ve ever seen. You can check out the official video from [Abyss] after the break, and the wild competition video after the break.

[Read more...]

Hackaday links: August 22, 2010

EL back-lit keyboard

A couple bucks worth of EL wire gives a nice green glow to [Mark Shasha's] T400 Elite. Hopefully [Jeri Ellsworth] has some time to pull those how-to videos together so that we can make our own EL wire to replicate this hack.

Mini kaboom

This tiny cannon is right out of Night at the Museum. It works just like its much bigger brothers would; fill with powder, insert cannon ball, and light with a fuse. Both the introduction and the follow-up videos document the destruction of various objects using the diminutive weapon. [Thanks Thorsten]

Don’t close that browser

We use Google Chrome quite a bit because it tends to be more responsive when opening massive numbers of tabs while researching featured hacks. But there’s some things we don’t like about it. Lack of built-in PDF support under Ubuntu comes to mind, but a smaller thorn in our side is that closing the last tab will also close the browser window. [Ted Schaefer] got tired of the same thing so he wrote an extension called Last Tab Standing to trap that last browser tab, opening the default window instead of closing the browser.

Amiga demo winner

This 4K demo for the Amiga AGA is the top ranked submission from Breakpoint 2010. [Osgeld] tipped us off about this and made the point that although it’s four times the size of those 1K JavaScript demos, the Amiga code doesn’t get to take advantage a pre-existing framework like Java does enjoy the benefits of running inside of a browser . Is this doing more with less?

Transformers balloon sculptures

If you’re having trouble finding that art piece to fill up your dining room you should consider building transformers out of balloons. The sculpture above is a free-standing Optimus Prime but the artist has also turned out Megatron, Grimlock, and others. [Thanks W01F]

Behind the scenes of a 1K graphics demo

Programmer/designer [Steven Wittens] has posted a fantastic write-up on the black art of producing compact demo code, dissecting his own entry in the 1K JavaScript Demo Contest. The goal is to produce the best JavaScript demo that can be expressed in 1024 characters or less and works reliably across all standards-compliant web browsers.

[Wittens] details several techniques for creating a lot of visual flash in very few bytes, including the use of procedural graphics rather than fixed datasets, exploiting prime numbers to avoid obvious repetitions in movement, and strategically fudging formulas to save space while adding visual interest. These methods are just as applicable to other memory-constrained situations, not just JavaScript — some of the contest entries bear a resemblance to the compact microcontroller demos we’ve previously showcased, except running in your browser window.

The contest runs through September 10th, allowing ample time to come up with something even more clever. Whether he wins or not, we think [Steven] deserves special merit on account of having one of the most stylish blogs in recent memory!

Notacon call for papers

notaconbadge

Notacon has just announced their first round of talk selections. The Cleveland, OH area hacker conference will be celebrating its sixth year April 16th-19th. When we attended this year we saw talks that ranged from circuit bending to the infamous TSA bagcam. Self-taught silicon designer [Jeri Ellsworth] presented on FPGA demoing. [Trixter] covered his demo archiving process. You can find a video archive of this year’s talks here.

We’re really looking forward to the conference. [SigFLUP] is already on the schedule to cover Sega Genesis development. Get your talk in soon though; they’re already handing out space to the knitters.

LCD PIC graphics demo

[conville] has been pushing standard HD44780 character displays to the limit. Embedded above is an example spectrum analyzer and text scrolling demo. Below you’ll find a scope demo. Both of these are created using a PIC 16F688 that dynamically rewrites a custom character set to create the animation. You can find the source code on mikrocontroller.net. [Read more...]

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