Day: March 24, 2020

Coronavirus Testing: Just The Facts

March 24, 2020 by 42 Comments

The news these days is dominated by the one big story: the COVID-19 pandemic. Since the first reports of infection surfaced in China sometime in late 2019, the novel coronavirus that causes the disease, bloodlessly dubbed SARS-CoV-19, has swept around the globe destroying lives, livelihoods, and economies. Getting a handle on the disease has required drastic actions by governments and sacrifices by citizens as we try to slow the rate of infection

As with all infectious diseases, getting ahead of COVID-19 is a numbers game. To fight the spread of the virus, we need to know who has it, where they are, where they’ve been, and whom they’ve had contact with. If we are unable to gather the information needed to isolate potential carriers, all that we can do is impose mass quarantines and hope for the best. Hence the need for mass COVID-19 testing, and the understandable hue and cry about its slow pace and the limited availability of test kits.

But what exactly do these test kits contain? What makes mass testing so difficult to implement? As we shall see, COVID-19 testing is anything but simple, even if the underlying technology, PCR, is well-understood and readily available. A lot of the bottlenecks are, as usual, bureaucratic, but there are technical limits too. Luckily, there are clever ways around those restrictions, but understanding the basics of COVID-19 testing is the best place to start.

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Breaking Into A Secure Facility: STM32 Flash

March 24, 2020 by 20 Comments

In a perfect world, everything would be open source. Our current world, on the other hand, has a lot of malicious actors and people willing to exploit trade secrets if given the opportunity, so chip manufacturers take a lot of measures to protect their customers’ products’ firmware. These methods aren’t perfect, though, as [zapb] shows while taking a deeper look into an STM microcontroller.

The STM32F0 and F1 chips rely on various methods of protecting their firmware. The F0 has its debug interface permanently switched off, but the F1 still allows users access to this interface. It uses flash memory read-out protection instead, which has its own set of vulnerabilities. By generating exceptions and exploiting the intended functions of the chip during those exceptions, memory values can be read out of the processor despite the memory read-out protection.

This is a very detailed breakdown of this specific attack on theses controllers, but it isn’t “perfect”. It requires physical access to the debug interface, plus [zapb] was only able to extract about 94% of the internal memory. That being said, while it would be in STM’s best interests to fix the issue, it’s not the worst attack we’ve ever seen on a piece of hardware.

Inverse Kinematics Robot Arm Magna-Doodles The Time For You

March 24, 2020 by 8 Comments

Following a surge of creativity fueled by the current lockdown, [Diglo] writes in with his tabletop clock driven by a robotic arm drawing on a Magna Doodle tablet. And if you have one of those still lying around with some old toys and don’t mind cannibalizing it for the project, you too can follow along the source files to build your own.

The clock works by exploiting the principle that Magna Doodle tablets work by being drawn on with a magnetic stylus. That way, to draw on one of them you don’t need to add a point of articulation to bring the pen up and down, [Diglo] simply attached a controllable electromagnet to the end of a two-dimensional SCARA arm. In total, the whole build uses three stepper motors, two to control the movement of the arm, and one on the back of the tablet to sweep a magnetic bar which “erases” it.

This clock is similar to another we’ve featured a few years ago, which also used a Magna Doodle, but greatly improves on the idea. If a Magna Doodle seems too childish to build a magnetic clock however, there’s always ferrofluidic displays to try to dip your fingers into, but we really think you should watch this one in action after the break first.

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