Machining Copper From Algaecide

August 18, 2024 by Al Williams 5 Comments

We love it when we find someone on the Internet who has the exact same problem we do and then solves it. [Hyperspace Pirate] starts a recent video by saying, “Oh no! I need to get rid of the algae in my pond, but I bought too much algaecide. If only there were a way to turn all this excess into CNC machined parts.” OK, we’ll admit that we don’t actually have this problem, but maybe you do?

Algaecide is typically made with copper sulfate. There are several ways to extract the copper, and while it is a little more expensive than buying copper, it is cost-competitive. Electrolysis works, but it takes a lot of power and time. Instead, he puts a more reactive metal in the liquid to generate a different sulfate, and the copper should precipitate out.

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Quantum Sensor Uses Synthetic Diamond

August 18, 2024 by Al Williams 3 Comments

Diamonds are nearly perfect crystals, but not totally perfect. The defects in these crystals give the stones their characteristic colors. But one type of defect, the NV — nitrogen-vacancy — center, can hold a particular spin, and you can change that spin with the correct application of energy. [Asianometry] explains why this is important in the video below.

Interestingly, even at room temperature, an NV center stays stable for a long time. Even more importantly, you can measure the spin nondestructively by detecting light emissions from the center.

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Hackaday Links: August 18, 2024

August 18, 2024 by Dan Maloney 4 Comments

They’re back! The San Francisco autonomous vehicle hijinks, that is, as Waymo’s fleet of driverless cars recently took up the fun new hobby of honking their horns in the wee hours of the morning. Meat-based neighbors of a Waymo parking lot in the South Market neighborhood took offense at the fleet of autonomous vehicles sounding off at 4:00 AM as they shuffled themselves around in the parking lot in a slow-motion ballet of undetermined purpose. The horn-honking is apparently by design, as the cars are programmed to tootle their horn trumpets melodiously if they detect another vehicle backing up into them. That’s understandable; we’ve tootled ourselves under these conditions, with vigor, even. But when the parking lot is full of cars that (presumably) can’t hear the honking and (also presumably) know where the other driverless vehicles are as well as their intent, what’s the point? Luckily, Waymo is on the case, as they issued a fix to keep the peace. Unfortunately, it sounds like the fix is just to geofence the lot and inhibit honking there, which seems like just a band-aid to us.

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Zero-dimensional PONG game built on a perfboard.

2024 Tiny Games Contest: Coming At Ya With Zero-Dimensional PONG

August 18, 2024 by Kristina Panos 5 Comments

A decade is a long time to carry around a project idea in your head. Fortunately, the Tiny Games Contest happens to coincide with [Senile Data Systems]’s getting back into ATMega programming, so they can finally make their zero-dimensional PONG dreams come true (and have the chance at great prizes, too, of course).

If you don’t already get what’s going on here, zero-dimensional PONG takes 1D PONG and turns it on the short side. Imagine the light coming toward you, then moving away toward your opponent, and you have the basic idea. So, how is this done? Pulse-width modulation controls the brightness of the LED, and, well, you have to be pretty fast, although there is a small margin for the inevitable error.

In the video after the break, you can watch [SDS] play themselves using a red/green LED. Player one must press the button when red is fully lit and green is off, and player two goes when green is fully lit and red is off. The cool thing is that this game uses sockets, so it can use any LED. There are nine difficulty levels to control the PWM speed, so one can really test one’s reaction time.

If you want to build one of these, you’ll need an ATtiny2313 or something similar, a couple of buttons, a display, and the optional but fun buzzer. The well-commented code is available through [Senile Data Systems]’s site.

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Meta Doesn’t Allow Camera Access On VR Headsets, So Here’s A Workaround

August 18, 2024 by Donald Papp 13 Comments

The cameras at the front of Meta’s Quest VR headsets are off-limits to developers, but developer [Michael Gschwandtner] created a workaround (Linkedin post) and shared implementation details with a VR news site.

The view isn’t a pure camera feed (it includes virtual and UI elements) but it’s a clever workaround.

The demo shows object detection via MobileNet V2, which we’ve seen used for machine vision on embedded systems like the Raspberry Pi. In this case it is running locally on the VR headset, automatically identifying objects even though the app cannot directly access the front-facing cameras to see what’s in front of it.

The workaround is conceptually simple, and leverages the headset’s ability to cast its video feed over Wi-Fi to other devices. This feature is normally used for people to share and spectate VR gameplay.

First, [Gschwandtner]’s app sets up passthrough video, which means that the camera feed from the front of the headset is used as background in VR, creating a mixed-reality environment. Then the app essentially spawns itself a Chromium browser, and casts its video feed to itself. It is this video that is used to — in a roundabout way — access what the cameras see.

The resulting view isn’t really direct from the cameras, it’s akin to snapshotting a through-the-headset view which means it contains virtual elements like the UI. Still, with passthrough turned on it is a pretty clever workaround that is contained entirely on-device.

Meta is hesitant to give developers direct access to camera views on their VR headset, and while John Carmack (former Meta consulting CTO) thinks it’s worth opening up and can be done safely, it’s not there yet.

Reverse-Engineering The AMD Secure Processor Inside The CPU

August 18, 2024 by Maya Posch 10 Comments

On an x86 system the BIOS is the first part of the system to become active along with the basic CPU core(s) functionality, or so things used to be until Intel introduced its Management Engine (IME) and AMD its AMD Secure Processor (AMD-SP). These are low-level, trusted execution environments, which in the case of AMD-SP involves a Cortex-A5 ARM processor that together with the Cryptographic Co-Processor (CCP) block in the CPU perform basic initialization functions that would previously have been associated with the (UEFI) BIOS like DRAM initialization, but also loading of encrypted (AGESA) firmware from external SPI Flash ROM. Only once the AMD-SP environment has run through all the initialization steps will the x86 cores be allowed to start up.

In a detailed teardown by [Specter] over at the Dayzerosec blog the AMD-SP’s elements, the used memory map and integration into the rest of the CPU die are detailed, with a follow-up article covering the workings of the CCP. The latter is used both by the AMD-SP as well as being part of the cryptography hardware acceleration ISA offered to the OS. Where security researchers are interested in the AMD-SP (and IME) is due to the fascinating attack vectors, with the IME having been the most targeted, but AMD-SP having its own vulnerabilities, including in related modules, such as an injection attack against AMD’s Secure Encrypted Virtualization (SEV).

Although both AMD and Intel are rather proud of how these bootstrapping systems enable TPM, secure virtualization and so on, their added complexity and presence invisible to the operating system clearly come with some serious trade-offs. With neither company willing to allow a security audit, it seems it’s up to security researchers to do so forcefully.

Categorizing Steel

August 18, 2024 by Al Williams 24 Comments

In the movie Conan the Barbarian, we hear a great deal about “the riddle of steel.” We are never told exactly what that riddle is, but in modern times, it might be: What’s the difference between 4150 and 1020 steel? If you’ve been around a machine shop, you’ve probably heard the AISI/SAE numbers, but if you didn’t know what they mean, [Jason Lonon] can help. The video below covers what the grade numbers mean in detail.

The four digits are actually two separate two-digit numbers. Sometimes, there will be five digits, in which case it is a two-digit number followed by a three-digit number. The first two digits tell you the actual type of steel. For example, 10 is ordinary steel, while 41 is chromium molybdenum steel. The last two or three digits indicate how much carbon is in the steel. If that number is, say, 40, then the steel contains approximately 0.40% carbon.

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