Veronica VGA board finalized

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The latest update in the Veronica 6502 computer project is this finalized VGA board which now has a home in the machine’s backplane.

We’ve been glued to the updates [Quinn Dunki] has been posting about the project for many months now. Getting the GPU working proved to take quite a bit of time, but we learned a ton just by following along. The video output had humble beginnings way back in March. That breadboarded circuit got complicated very quickly and that was before it was even interfaced with the CPU. As you can see from the image above, etching and populating the GPU board really cleans up the build. We’re sure it’s robust enough to move around at this point. We wonder if she’s planning on showing it off at a Maker Faire or another geeky gathering?

It really has become clear how wise [Quinn] was to design a backplane board early on. It plays right into the modular concept. She was even smart enough to include that SIL pin header on the near side of the board which was used heavily while prototyping this video module.

Interfacing a GPU with a CPU

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[Quinn Dunki] pulled together many months worth of work by interfacing her GPU with the CPU. This is one of the major points in her Veronica project which aims to build a computer from the ground up.

We’ve seen quite a number of posts from her regarding the AVR-powered GPU. So far the development of that component has been happening separately from the 6502 centered CPU. But putting them together is anything but trivial. The timing issues that were so important to consider when developing the GPU get even hairier when it comes writing to the VRAM from an external component. Her first thought was to share a portion of the external RAM between the CPU and GPU as a way to push rendering commands from one to the other. This proved troublesome both in timing and in the number of pins available on the AVR chip. She ended up using something of a virtual register on the AVR chip that can receive commands from the CPU asynchronously. Timing dictates that these commands be written only during vertical blanking so this virtual register also acts as a status register to let the CPU know when it can send the next command.

Her post is packed with the theory behind the design, timing tests on the oscilloscope, and a rather intimidating schematic. But the most important part is the video showing her success in the end.

25 GPUs brute force 348 billion hashes per second to crack your passwords

It’s our understanding that the video game industry has long been a driving force in new and better graphics processing hardware. But they’re not the only benefactors to these advances. As we’ve heard before, a graphics processing unit is uniquely qualified to process encryption hashes quickly (we’ve seen this with bitcoin mining). This project strings together 25 GPU cards in 5 servers to form a super fast brute force attack. It’s so fast that the actual specs are beyond our comprehension. How can one understand 348 billion hashes per second?

The testing was used on a collection of password hashes using LM and NTLM protocols. The NTLM is a bit stronger and fared better than the LM, but that’s not actually saying much. An eight character NTLM password will fall in 5.5 hours, while a 14 character LM hash makes it only about six minutes before the solution is discovered. Of course this type of hardware is only good if you have a copy of the password hashes themselves. Login protocols will lock out after a certain number of attempts and have measures in place to slow down automated systems like this one.

[via Boing Boing]

PC temperature monitoring system lights up when things get hot

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[Taylor] popped a new graphics card into his computer, but before he could settle in for a round of gaming, his card started to overheat. He eventually tracked the problem down to an undersized power supply, but the prospect of cooking his new GPU to death made him think twice about how he was monitoring his system’s health.

To continually keep tabs on his video card’s temperature going forward, he put together a small circuit that will alert him if things start to get too hot. He mounted a small temperature sensor on his graphics card near the GPU, wiring it to an Arduino. The Arduino monitors his video card, lighting an RGB LED blue if conditions are alright. If the temperature rises above 50C, the LED changes to red, signaling a problem.

We’re aware that there are all sorts of software applications that can monitor component temperatures for you, but the appeal of [Taylor’s] system is that it can be easily seen from across the room rather than via the desktop. That said, we think that his system could take advantage of his PC’s case fan lighting for a more visible warning, and it wouldn’t hurt to wire in an auto-shutdown feature in case his computer overheats while he’s away.

Paddle controller for GPU overclocking

[Fred] likes to squeeze every cycle possible out of his graphics card. But sometimes pushing the clock speed too high causes corruption. He figured out a way to turn a knob to adjust the clock speed while your applications are still running.

The actuator seen above is a Griffin Powermate 3.0. It’s a USB peripheral which is meant to be used for anything you can imagine. [Fred] uses an AutoHotKey script that he wrote to capture the input from the spinner, process that information, then adjust GPU clock speed in the background. Since the clock on his ATi Radeon 5800 can be adjusted using the AMD GPU clock tool, it’s an easy choice for this application. Now better graphics are at the tips of his fingers. See for yourself in the video after the break.

Of course if you don’t want to shell out for the fancy hardware you could always build your own paddle controller.

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Converting PWM to DC signaling for more precise fan control

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[hedgehoginventions] wrote in to share a little modification he made to his video card in order to keep it from overheating during strenuous 3D tasks. Having swapped out the stock cooler on his Nvidia 9600GT graphics card, he found that it did not need to utilize the fan while doing mundane things like checking email, but that it still required extra air flow while playing games.

He figured he get the fan to shut off by tweaking the PWM signal, but he found that he could not get the duty cycle under 20% using software, which still caused the fan to run at all times. The circuit he built takes the PWM signal output by the card, cleaning it up before converting it to a corresponding DC voltage. The fan then runs at the same speed it would if driven directly by the PWM signal, though it can now turn off completely when not required.

It’s a nice way to do automatic fan control when you can’t otherwise get your GPU fan to shut off. Nice work!

Creating music from GPU noise

Yep, that’s a picture of a Laptop rocking out on an electric guitar. In what can only be described as a truly bizarre hack [CNLohr] discovered that the RF noise from the computer can be used to play music through the guitar’s pickup.

Check out the clip after the break to hear an annoying, but very discernible rendition of Jingle Bells. Once [CNLohr] stumbled onto the fact that changes in what the graphic processing unit is doing was affecting the pitch detected by the pickup he started writing some code. Now he’s got a program that automatically calculates the size of the window, and produces a white square on a black background to dial in the GPU at the right frequencies.

He mentions in the notes accompanying his video that he had to turn off Vsync to get this to work right. We don’t understand why but we’d love to hear what you think in the comments.

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