The Earth orbits the Sun every 365.256 days. Because this number isn’t a whole number, an extra day is tacked onto February every four years, unless the year is evenly divisible by 100, except in cases where the year is divisible by 400, or something like that. To commemorate this calendar hack, here’s some stuff that has rolled in over the last week or so.
[Brian] sent in this marble-based sequencer that sounds like someone is running MIDI into an Atari 2600. There are photoresistors in there somewhere, and it really reminds us of those thingamagoop robots.
[Mike] uses YouTube as his music library. While this is a perfectly acceptable way to listen to music, the user interface is terrible. To solve this problem, [Mike] is downloading videos from the command line, automagically converting them to MP3, and playing them over speakers. It works well with SSH, so we’ll call this a win.
Key card lock
[valenitn] just joined the MIT Media Lab, but something was terribly wrong with his keys – an ID card was required to get into the building, but a key was necessary to get into his office. He doesn’t need the key anymore, at least since he modded his office door. Check out the video.
Pop Tart Cat is everywhere
[skywodd] saw our writeup on the Maximite Basic computer and figured he could send in a project he’s been working on. He programmed his Maximite to sing the nyan cat song and then created a BASIC music player. Nice job, [skywodd].
Not sure if brilliant or insane
[Vikash] ran across a forum post where a user named [I Shooter] describes his setup to dual-boot Windows and Linux: [I Shooter] connected data cables to a pair of SATA hard drives, one loaded up with Windows, the other with Linux. The power cables are switched using relays so only one drive is powered at a time. [I Shooter] gets a ton of points for creativity, but there’s a reason this brute force hardware dual-boot setup isn’t more common. We wish there were pictures of this one.
[Flowolf] added an auto-locking RFID entry system to his front door. He used our favorite fabrication system, acrylic and threaded rod (we also like to throw in aluminum angle bracket from time to time). The support structure mounts underneath the escutcheon plate for the lockset, keeping the main acrylic sheet flat against the door.
An RFID reader and Arduino run the system, with a button inside to unlock the door. But if power were to fail, you will still be able to get in or out manually. When you are using the electronic system, a stepper motor connected to the geared lock knob by a chain is what grants access, then revokes it again five seconds later. The wire going up out of the this image is for a switch that lets the unit sense when the door is closed.
As shown in the video after the break, you can turn the auto-lock feature off. But we’d like to see an emergency entry feature, like a knock-based lock, because eventually you will leave without your keys!
Continue reading “Geared system adds RFID to regular door locks”
[John Boxall] took a different route for a single-input combination lock. This unit uses a Ping ultrasonic range finder to input a four digit code. It’s a hardware upgrade, but uses the same basic concept as his button-based combo lock. That design used an Arduino to measure how long you hold down a single button, with a one second pause between inputs, to enter the code. This one also uses timing to establish when each digit is read, but that digit is grabbed as the distance between your hand and the sensor.
There are things we like and dislike about the redesign. This is obviously much more expensive than other button-based locks like this garage door opener we built. If we were to run with [John’s] design, we might spring for the Ping sensor (because it’s a pretty cool input) and replace he character LCD with an LED or two. The other drawback that we see here is that it may be easy for someone to steal your code by watching from afar. Still, we love the project and think you will too after seeing the demo clip below.
Continue reading “Ultrasonic combo lock”
[Arshad Pathan] let us know about his latest project, a modular code lock that can be adapted to many different situations.
The user interface is made up of a character LCD screen and a 3×4 keypad. For this example [Arshad] is using a stepper motor as the locking mechanism. When the board is first powered up it runs the stepper in one direction until receiving input from a limiting switch. In this way, the microcontroller calibrates itself to ensure the lock is in a known position. From there it waits for user input. An unlocked door can be locked at any time by pressing the * key. Unlocking requires entry of the correct password. And a password can be changed by entering 9999 (followed by the old password when prompted).
In the video after the break [Arshad] does a great job of demonstrating the various modes which he has programmed. This stands on its own, but we always love to have more details so we’ve asked if [Arshad] is willing to share a schematic and the source code. We’ll update this post if we hear back from him.
Update: [Arshad] sent in a couple of schematics which can be found after the break.
Continue reading “Full featured security lock demonstration”
[Eric] needed a project for his digital logic design class, and decided on a lock that open in response to a specific pattern of knocks. This is a fairly common project that we’ve seen a few builds with ‘knock locks,’ but this one doesn’t use a microcontroller. Instead, it uses individual logic chips.
The lock senses the knocks with a piezo, just like every other build we’ve seen. Unlike the other builds, the knock pattern is then digitized and stored in an EEPROM. [Eric] only used 12 chip for this build, a feat he could accomplish with a few digital tricks, like making an inverter by tying one XOR input high.
We’ve seen a 555-based knock lock before, but getting the timing right with that seems a little maddening. [Eric]’s build seems much more user-friendly, and has the added bonus of being programmed by knocking instead of turning potentiometers. Check out [Eric]’s knock lock after the break.
Continue reading “Knock lock with logic chips”
[Dombeef] made a locking enclosure for his sketchbook. The diamond seen in the center of the book is formed by the four sliding parts of the lock. Only with the proper movements will you get the cover open so you can plan your next hack.
He was inspired by this wooden version created by artist [Kagen Schaefer]. There were no tips about how the mechanism was made but a bit of deep thinking led [Dombeef] to discover the secret. Being the papercraft ninja that he is (he makes things like gyroscopes, strandbeests, and claws) this was created using cardstock as the parts. There is a wooden pin on the right that serves as the latch. Each of the four puzzle pieces moves around each other to free a slot from its hold on the notched latch.
There is a diagram showing the parts and their movements in the post linked above. [Dombeef] also mentioned an animated GIF that he promises to publish soon.