Most projects we feature are of the metal/wire/wood variety, but there is an entire community devoting to making very interesting and intricate things out of paper. Imgur user [Criand] has been hard at work on his own project made entirely out of paper, a combination lock that can hold a secret message (reddit post).
The motivation for the project was as a present for a significant other, wherein a message is hidden within a cryptex-like device and secured with a combination that is of significance to both of them. This is similar to how a combination bike lock works as well, where a series of tumblers lines up to allow a notched shaft to pass through. The only difference here is that the tiny parts that make up the lock are made out of paper instead of steel.
This project could also be used to gain a greater understanding of lock design and locksport, if you’ve ever been curious as to how this particular type of lock works, although this particular one could easily be defeated by a pair of scissors (but it could easily cover rock). If papercraft is more of your style though, we’ve also seen entire gyroscopes and strandbeests made of paper!
First we start with some protection… for your USB charged devices. Here’s a USB Condom which acts as a pass-through for the power rails but not the data lines. This prevents untrusted charger security exploits. [Thanks Markus]
[OutKastz] seems to think he’s uncovered a price matching conspiracy at Best Buy. His post references an HDTV video wall he has built. But he also discovered that there are two different version of the same television sold as the same SKU. His theory is that this prevents the big box from matching prices on half of their inventory.
When you’re in need of some breadboarding action with your Raspberry Pi and want to make it as painless as possible you need to build your own Pi Cobbler. This is the diy version of an Adafruit product, built using a couple of pin headers, stripboard, and an IDE cable.
Speaking of Adafruit, did you see Ladyada’s teardown of an ICEdot crash sensor?
[Phineas] is showing off a really really small hexacopter. Check out the maiden flight, as well as first indoor and first outdoor tests.
Perhaps this coded entry system will inspire a future project for you. It uses piezo elements to enter a code which unlocks the back door to the company. The glass door already had a series of large dots painted on it. This turns out to be a nice interface for a four button code system.
Many projects use a Raspberry Pi as a web server. But there is more than just one flavor available. [Jeremy Morgan] performed a variety of Pi server benchmarks using Nginx, Monkey, Lighttpd, and Apache. [Thanks Walter]
Can an old TV antenna reflector be used to boost the range of a WiFi dongle? We’re a bit skeptical. Let us know what you think in the comments.
And finally, we do wish there was more information on this upright piano used to play Doom [Thanks Itay].
Here’s a really fascinating circuit that implements a combination lock using relays and logic gates. Even with the schematic and written explanation of how it works we’re still left somewhat in the dark. We’ll either pull out some paper and do it by hand this weekend, or build it chunk by chunk in a simulator like Atanua. Either way, the project sparked our interest enough that we want to get elbow deep into its inner workings.
From the description we know that it uses a combination of CD4017, CD4030, CD4072, and CD4081 chips. You’re probably familiar with the 4017 which is a decade counter popular in a lot of project. The other chips provide XOR, OR, and AND gates respectively. The relays were chosen for two purposes. One of them activates when a correct combination has been entered, effectively serving as the output for the combo lock. The other two are for activating the clock and affecting a reset if the wrong combination is entered.
It makes us wonder if this would be incredibly simple to brute force the combination by listening for sound of the reset relay activating? It’s hard to tell from the video after the break if you can discern a wrong digit from a right once just based on sound.
Continue reading “Combo lock uses relays and logic gates”
[Admiral Aaron Ravensdale], fine craftsman of steampunk wares, just finished up a new project. It’s a sketchbook protected by two layers of security, covered in gilded leather and drenched in the expositions of a [Jules Verne] novel.
The first layer of security for this sketchbook is a combination lock. On the cover are four switches, each with four positions. These are connected to a PICAXE microcontroller which goes to the next stage of the lock once the correct combination is entered.
The book’s security also includes a knock sensor. With a small piezo element hidden under the cover, [Ravensdale] deeds to tap the book with a specific pattern before it opens. The mechanical part is a small hobby servo also mounted to the cover that releases a pair of brass clasps once both locks are opened.
Like all of the [Admiral]’s builds, it’s a fine piece of craftsmanship, equally well suited to take on a holiday with the baron or to the opium dens of Ceylon.
You can check out [Admiral Ravensdale]’s demo of his sketchbook after the break.
Continue reading “A steampunk combination sketchbook”