GUI Window Manager On An AVR Chip

avr-window-manager-gui

This project is reminiscent of the old days when window managers were an amazing new idea. The difference is that this window-based GUI is running on an ATmega1284 microcontroller. But the behavior and speed of the interface is pretty much exactly what you’d expect if working on an early 90’s home computer. It even uses a mouse as input.

So how is this even possible? The key to the project is a serial to VGA module which handles the heavy lifting involved with generating a VGA signal. We featured one of [Andrew’s] past projects which used an AVR chip to generate the VGA signal. But that doesn’t leave nearly enough cycles to implement something like a window manager, not to mention the fact that it got nowhere near the resolution shown here.

He uses a serial mouse with an RS-232 converter chip to interact with the windows. This is best shown in his video after the break. He’s able to generate and interact with new windows. He even implemented a set of rudimentary controls which allow him to adjust the theme of the windows and drive the audio playback feature included on that VGA controller he’s using.

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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.

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AVR VGA Generator

avr-vga-generator

This simple circuitry makes up the hardware for [Andrew’s] AVR-based VGA generator. He managed to get an ATmega1284 to output a stable VGA signal. Anyone who’s looked into the VGA standard will know that this is quite an accomplishment. That’s because VGA is all about timing, and that presented him with a problem almost immediately.

The chip is meant to run at a top speed of 20 MHz. [Andrew] did manage to get code written that implemented the horizontal and vertical sync at this speed. But there weren’t enough clock cycles left to deal with frame buffering. His solution was to overclock the chip to 25 MHz. We assume he chose that because he had a crystal on hand, because we think it would have been easier to use a 25.174 MHz crystal which is one of the speeds listed in the specification.

Red, green, and blue each get their own two-bit range selected via a set of resistors for a total of 64 colors. As you can see in the video after the break, the 128×96 pixel video is up and running. [Andrew] plans to enlarge the scope of the project from here to make it more versatile than just showing standard images. The code (written in assembly) is available at his GitHub repository.

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Color NTSC Video Directly From An AVR Chip

color-ntsc-from-avr-chip

We’ve seen composite video out from AVR chips many times before. But we can’t remember coming across one that managed to produce a color signal. This project does just that, producing a color video signal from an ATmega168 without using external integrated circuits.

[CNLohr] is seen here showing off his accomplishment. You’ll remember him from the glass-slide PCB server project he’s been working on recently. This time around it’s a small piece of gaming hardware which he’s working on. But using four pins from the microcontroller, connected via resistors in parallel, he is able to generate a color NTSC signal without using a chip like the AD723.

After the break you can see the two minute demo in which he shows the game running for just an moment, then gives a general overview of how the signals are being built. There isn’t a ton of explanation, but he did post his code as well as a resource for you to teach yourself more about the NTSC standard. Maybe you can make a color version of that AVR tetris game?

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Stereoscopic Display Art Installation

stereoscopic-display

This rig is something of a museum or art installation, but the concept is so simple we thought it could easily inspire your next project. The two mirrors and two video sources make up a stereoscopic display.

The user sits between two displays (computer monitors shown here, but the post also shows images projected on two walls of a room). A pair of mirrors mounted at forty-five degrees form the eye pieces. It’s a V-shaped mirror assembly in which the narrow end pointing toward the bridge of the user’s nose. The mirrors reflect the images from the monitors, giving a different view for each eye.

In this case each monitor is playing back a video loop, but one is just slightly longer than the other. Each monitor has a potentiometer in front of it. The user can turn them to speed or slow the playback in an attempt to bring the video back into sync. We don’t think we’d replicate that portion of the project. But it might be fun to view some stereoscopic clips in this way. There’s even instructions on how two cameras were used to record the scenes.

You can get a closer view of the test apparatus in the clip after the jump.

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Camera Adapter For A Microscope

camera-adapter-for-stereo-microscope

[Steve] really has a nice microscope setup in his lab now that he built a video camera adapter for his stereo microscope. The image above shows the magnified view of the circuit board on the LCD screen behind it. This lets him work without needing to be in position to look through the eye pieces. The hack is a perfect complement to the custom stand he fabricated for the scope.

The camera attachment can be seen attached to the right lens of the scope. It’s an old security camera which he already had on hand. The stock lens wasn’t going to bring the picture into focus, but he had some different optics on hand and one of them fit the bill perfectly. The rest of the project involves fabricating the adapter ring on his lathe. It slips perfectly over the eyepiece and even allows him a bit of adjustment to get the focal length right. The best view of this is shown off in the video after the break.

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Launching A Glider From Space

We get a ton of tips about weather balloon launches taking hobby electronics into space. But every once in a while one of them stands out from the rest. This project does send an electronic payload into space, but it also lets [David] fly his hardware back from near-space using an RC airplane.

The return vehicle is unpowered, but that shouldn’t be a problem as launching from a weather balloon will provide plenty of altitude for the flight. Because the temperature experienced in that part of the atmosphere is so cold [David] had to take several things into account. Obviously you want your batteries and control electronics to be insulated from the cold. But something that doesn’t usually pop into mind are issues with the servo motors which run the glider’s flaps. They usually have some white grease on the gears. At temps as low as -50C that grease will harden and make the servo stop working so he made sure to clean the gears thoroughly before the flight.

Unfortunately [David] had several problems capturing images and recorded video from the ground station. But his write up is still a fun read and the clip after the break gives a general overview of the entire project from the nose camera of the glider.

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