Preventing Embedded Fails with Watchdogs

Watchdog timers are an often overlooked feature of microcontrollers. They function as failsafes to reset the device in case of a software failure. If your code somehow ends up in an infinite loop, the watchdog will trigger. This is a necessity for safety critical devices. If the firmware in a pacemaker or a aircraft’s avionics system gets stuck, it isn’t going to end well.

In this oldie-but-goodie, [Jack Ganssle] provides us with a great write up on watchdog timers. This tells the story of a failed Clementine spacecraft mission that could have been saved by a watchdog, and elaborates on …read more

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Low Tech High Safety and the NYC Subway System

The year is 1894. You are designing a train system for a large city. Your boss informs you that the mayor’s office wants assurances that trains can’t have wrecks. The system will start small, but it is going to get big and complex over time with tracks crossing and switching. Remember, it is 1894, so computing and wireless tech are barely science fiction at this point. The answer — at least for the New York City subway system — is a clever system of signals and interlocks that make great use of the technology of the day. Bernard S. Greenberg …read more

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Doxxing: What It Is How You Can Avoid It

Doxxing means publishing private information about someone online to harass or intimidate them. It has ruined reputations and caused untold distress to hundreds of people. On occasion, doxxing has resulted in injury or even death. Being doxxed can have… Continue reading Doxxing: What It Is How You Can Avoid It

A Safe, Ducted Drone With No Visible Blades

We love a good drone build here at Hackaday, but no matter how much care is taken, exposed propellers are always a risk: you don’t have to look far on the web to see videos to prove it. Conventional prop-guards like those seen on consumer drones often only protect the side of the propeller, not the top, and the same problem goes for EDFs. [Stefano Rivellini]’s solution was to take some EDFs and place them in the middle of large carbon fibre thrust tubes, making it impossible to get anywhere near the moving parts. The creation is described as a …read more

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Shape Shifting Structures Work With Magnets

In The Dark Knight, Lucius Fox shows Bruce Wayne a neat bit of memory weave fabric. In its resting state, it is a light, flexible material, but when an electrical current is applied, it pops into a pre-programmed shape. That shape could be a tent or a bat-themed paraglider. Science has not caught up to Hollywood in this regard, but the concept has been demonstrated in a material which increases its rigidity up to 318% within one second when placed in a magnetic field. Those numbers do not mean a lot by themselves, but increasing rigidity in a reversible, …read more

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Fail of the Week: How Not to Electric Vehicle

If you ever doubt the potential for catastrophe that mucking about with electric vehicles can present, check out the video below. It shows what can happen to a couple of Tesla battery modules when due regard to safety precautions isn’t paid.

The video comes to us by way of [Rich], a gearhead with a thing for Teslas. He clearly knows his way around the EV world, having rebuilt a flood-soaked Tesla, and aspires to open an EV repair shop. The disaster stems from a novelty vehicle he and friend [Lee] bought as a side project. The car was apparently once …read more

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3D Printer Warning: Heating Plastic To High Temps is Not Healthy

If you’ve ever tried to cut a piece of acrylic with a tool designed to cut wood or metal, you know that the plastic doesn’t cut in the same way that either of the other materials would. It melts at the cutting location, often gumming up the tool but always releasing a terrible smell that will encourage anyone who has tried this to get the proper plastic cutting tools instead of taking shortcuts. Other tools that heat up plastic also have this problem, as Gizmodo reported recently, and it turns out that the plastic particles aren’t just smelly, they’re toxic. …read more

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When Encryption isn’t ‘Safe’ Enough

Being on the hook for free services to friends and family members is a well-known risk for many professionals. Doctors get called in the middle of the night to see sick nieces and nephews, attorneys advise their siblings on traffic violations and airli… Continue reading When Encryption isn’t ‘Safe’ Enough