[Pekka] set himself up with quite the challenge – use an oscilloscope screen to display Quake in realtime – could it even be done? Old analog scope screens are just monochromatic CRTs but they are designed to draw waveforms, not render graphics.
Over the years Hackaday has tracked the evolution of scope-as-display hacks: Pong, Tetris, vector display and pre-rendered videos. Nothing that pushed boundaries quite like this.
[Pekka]’s solution starts off the same as many others, put the scope in X-Y mode and splice up your headphone cable – easy. He then had to figure out some way to create an audio signal that corresponded to the desire image. The famous “Youscope” example demos this, but that demo is pre-rendered. [Pekka] wanted to play Quake in realtime on the scope itself, not just watch a recording.
With only so much bandwidth available using a soundcard, [Pekka] figured he could draw a maximum of about a thousand lines on screen at a time. The first headache was that all of his audio cards had low-pass filters on them. No way around it, he adjusted his ceiling accordingly. ASIO and PortAudio were his tools of choice to create the audio on the fly from a queue of XY lines given.
To tell his audio engine what lines to draw, he solicited Darkplaces – an open source Quake rendering engine – and had it strip polygons down to the bare minimum. Then he had to whip out the digital hedge trimmers and continue pruning. This writeup really cannot do justice to all the ingenious tricks used to shove the most useful data possible through a headphone jack. If this kind of thing interests you at all, do yourself a favor and check out his well-illustrated project log.
In the end [Pekka] was not entirely happy with the results. The result is playable, but only just barely. The laptop struggles to keep it simple enough, the soundcard struggles to add enough detail and the scope struggles to display it all quickly enough. At the very least it sets the bar extraordinarily high for anyone looking to one-up him using this method. There is only so much water that can be squeezed from a rock.
See the video below of [Pekka] playing the first level of Quake.
Continue reading “Ultimate Oscilloscope Hack – Quake in Realtime”
[Damien] sent us a quick email to let us know that Micro Python, a lean and fast implementation of the Python scripting language on microcontrollers is now running on the ESP8266. You may remember him from his interview on Hackaday, back when Micro Python was still at the crowdfunding stage. His campaign gathered £97k (for a £15k objective) and its comment section let us know that the backers are very happy with what he delivered.
As the very cheap ESP8266 Wifi module is gathering a lot of attention, he implemented support for it. You may use the dedicated files in the main repository ESP8266 folder together with esp-open-sdk or simply use the precompiled binary available here. Unfortunately the software doesn’t have WiFi support yet, as it’s only a Python REPL prompt over UART at the moment. Contributors are therefore welcome to help speed up the development!
Check out Samus looking boss in this pixelated image. Who would have thought of using Tetris as a canvas for these types of graphics? Coming up with the original idea of strategically clearing and leaving Tetris pieces to end up with what is shown above is hard enough. But how in the heck do you implement the algorithm that generated this programmatically?
First off, two thing should not be surprising about this. It wasn’t manually generated during normal gameplay. That would be beyond savant level. The other thing to note is that the order in which pieces occurred was not random, but strategically calculated by the algorithm. The challenge is not only to occupy and clear the correct pixels, but to make sure the correctly colored pieces remain.
You need to see the fast-motion video embedded after the break to fully appreciate the coding masterpiece at work. We’re not going to try to paraphrase how the algorithms functions, but get comfy with the link above which walks through all of the theory (in addition to supplying the code so you can try it yourself).
Continue reading “Using Tetris Like MS Paint”
The Excel subreddit exploded earlier this week when redditor [AyrA_ch] shared his custom spreadsheet that allowed him to play video files on a locked-down work computer. How locked down? With no access to Windows Media Player and IE7 as the only browser (all plugins disabled, no HTML5), Excel became the unlikely hero to cure a 3-hour boredom stint.
Behind the cascade of rectangles and in the land of the Excel macro, [AyrA_ch] took advantage of the program’s VBA (Visual Basic for Applications) functions to circumvent the computer’s restrictions. Although VBA typically serves the more-complex-than-usual macro, it can also invoke some Windows API commands, one of which calls Windows Media Player. The Excel file includes a working playlist and some rudimentary controls: play, pause, stop, etc. as well as an inspired pie chart countdown timer.
As clever as this hack is, the best feature is much more subtle: tricking in-house big brother. [AyrA_ch]’s computer ran an application to monitor process usage, but any videos played through the spreadsheet were attributed to Excel, ensuring the process usage stayed on target. You can download it for yourself over on GitHub.
No one is sitting around their workbench trying to come up with the next great oscilloscope or multimeter, but function generators still remain one of the pieces of test equipment anyone – even someone with an Arduino starter pack – can build at home. Most of these function generators aren’t very good; you’re lucky if you can get a sine wave above the audio spectrum. [Bruce Land] had the idea to play around with DMA channels on a PIC32 and ended up with a function generator that uses zero CPU cycles. It’s perfect for a homebrew function generator build, or even a very cool audio synthesizer.
The main obstacles to generating a good sine wave at high frequencies are a high sample rate and an accurate DAC. For homebrew function generators, it’s usually the sample rate that’s terrible; it’s hard pushing bits out a port that fast. By using the DMA channel on a PIC32, [Bruce] can shove arbitrary waveforms out of the chip without using any CPU cycles. By writing a sine wave, or any other wave for that matter, to memory, the PIC32 will just spit them out and leave the CPU to do more important work.
[Bruce] was able to generate a great-looking sine wave up to 200 kHz, and the highest amplitude of the harmonics was about 40db below the fundamental up to 100 kHz. That’s a spectacular sine wave, and the perfect basis for a DIY function generator build.
Star Wars: Yoda Stories was released by LucasArts in 1997 to minimal critical acclaim. As IGN said, “like Phantom Menace proved, just because it’s Star Wars doesn’t mean it’s good.” This didn’t stop [Zach] from playing it, and years later, taking an interest in reverse engineering the game.
[Zach]’s reverse engineering of Star Wars: Yoda Stories (google cache) takes a look at the game’s data file. This binary file is parsed by the game at run time to extract sound effects, sprites, and map tiles. Perhaps the best known game data file type was Doom’s WAD file, which had purpose built editing programs from third parties.
After a quick look at the data file in HxD, [Zach] began writing scripts in C# to extract different sections of the data file. Once the sections were found, more code was used to apply a color palette and generate bitmaps.
In the end, [Zach] managed to get a couple thousand tiles of the game’s data. He found some interesting ones, such as the sports car that he replaced the X-Wing with in his mod. The engine for an earlier Lucasarts game, Indiana Jones and His Desktop Adventures, should be very similar, and once we find the Mac install disk and a copy of ResEdit, we’ll post something on Hackaday.io.
[Gadget Addict] found out about a contest being held by a shoe seller. Their mobile app has a game very much like Bejeweled. The high scorer each month gets £500. His choices were to be better at the game than everyone else, or to be smarter. He chose the latter by writing a computer vision program to play the game.
There are two distinct parts of a hack like this one. The first is just figuring out a way to programmatically detect the game board and correctly identify each icon on it. This is an iPad game. [Gadget Addict] is mirroring the screen on his laptop, which gives him easy access to the game board and also allows for simulated swipes for automatic play. Above you can see two examples where black pixels may be counted in order to identify the icon. A set of secondary checks differentiates similar entries after the first filtering. The other part of the hack involves writing the algorithms to solve for the best move.
If you liked this one, check out a super-fast Bejeweled solver from several years back. We should also mention that this was just a proof of concept and [GA] never actually entered the contest.