MIT students Grant Jordan and Kyle Vogt found themselves in possession of a high-security safe -- the S&G 8400, a class-1 safe of the sort formerly used to store classified documents. They wanted to open it, but they lacked the combination and were unable to crack it using the sort of techniques that work on lesser strongboxen. So they build a safecracking robot that autodialled combination after combination (the robot excluded "impossible" combinations that couldn't be set due to material limitations of the mechanism, which substantially reduced the keyspace). They eventually opened the safe, but didn't find anything interesting in it.
We used a custom stepper motor to rotate the dialer head. The dialer head transmits torque to the dial via a piece of heavy duty surgical tubing. The stepper motor we chose has more than enough resolution to implement our algorithm, but it's not quite as fast as it could be. Stepper motors have an extremely high "holding torque", which is ideal in this situation since the dial must be held in place while the butterfly knob is being turned.
The head also contains an RC servo motor with a machined knob to mesh with the butterfly knob. This setup enables independent rotation of both the dial and butterfly knob. The stepper motor shaft is also connected to a high resolution optical encoder for position feedback. The encoder is mainly used to detect when safe is successfully opened. The torque required to open the safe when the correct combination is entered is much higher than the maximum torque of the stepper motor, so the encoder is programmed to report when the position error exceeds a certain threshold. Basically, the stepper motor stalls and the encoder flips out if the safe actually opens.
I suffer from mild RSI: a warning to stop, but one that goes away when I do stop. The trigger is using a mouse for extended periods. The alternatives for general everyday computer use aren’t great for my work habits, which center on precise pointing and clicking, so I’m in the bad habit of mousing […]
I got one of those bug-zapping LED lightbulbs, in hopes of murdering the flies drifting into my office during the increasingly warm and muggy Pennsylvania summer. I got mine from Home Depot, but the bulbs at Lowes, Wal-Mart and Amazon are all obviously identical. There are two lights in each bulb: an ultraviolet one inside […]
Despite the upfront cost, electric toothbrushes are much better at removing plaque than those freebies from the dentist’s office. For those who struggle to fill the American Dental Association’s recommended two minutes of brushing time, or anyone with limited dexterity, a sonic toothbrush can give your oral care routine a boost.To keep your chops healthy […]
Learning a new language will give your resume an upgrade, sure, but it will also provide a huge cognitive boost for mental tasks outside of translation and conversation. Bilingual brains have been shown to be better at handling multiple concurrent tasks, and gaining fluency in a new tongue is an amazing way to improve memory, […]
If you struggle to get a good night’s rest, consider replacing your pillows before dropping hundreds on a new mattress. You can give your tired neck a break with a 2-pack of memory foam pillows, available now in the Boing Boing Store.Each of these pillows is stuffed with cooling polyurethane foam that molds to your […]