Geared system adds RFID to regular door locks

[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!

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High speed stepper driving: 25k steps per second

Stepper motors are pretty easy to control with a microcontroller. But if you’re looking to run then at a high number of revolutions per second things get tricky pretty quickly. [Uwe’s] been learning about and building stepper drivers for years, and recently he decided to build a high-performance driver based on a MicroChip reference design.

As with the reference design, his board uses a dsPIC33. But instead of using a series of discrete MOSFETS to switch the signals to the motor, he sourced an L298N motor driver. That’s it sticking up next to the large capacitor. When driven hard it needs its own heat sink, which [Uwe] cut from a larger CPU heat sink. During development, he decided to use interrupt-based PWM rather than the hardware PWM offered by the dsPIC. It works, but he would go the other route if doing it again.

For the pedestrian, the video after the break has all the details you need. For those that really want to dive in, [Uwe’s] multi-paged write-up is worth bookmarking.

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Lighted acrylic Christmas ornaments

If you’ve gone to the trouble of building your own CNC mill we know you’re always on the lookout for things to use it for. [Boris Landoni] wrote in with just the thing for the holiday season; a set of lighted acrylic Christmas ornaments.

One of the interesting properties of acrylic is how it reacts when edge-lit. The material pipes the light, until it bounces off of a disturbance in the surface. The first step is to design the outline of the ornament as all cut edges will glow. Next, [Boris] uses artCAM to design the internal parts to be cut. This application translates the relief cuts necessary to really make your design shine (sorry, we couldn’t resist). The best examples of this are the angel and candle seen above.

Each of these acrylic pieces has a slot cut on the bottom to hug an LED. [Boris] used small project boxes with a PCB for that diode, as well as a button battery for power.

Ultrasonic combo lock

[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.

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How the Kindle Touch jailbreak was discovered

The Kindle Touch has been rooted! There’s a proof video embedded after the break, but the best part about this discovery is that [Yifan Lu] wrote in-depth about how he discovered and exploited a security hole in the device.

The process begins by getting a dump of the firmware. If you remove the case it’s not hard to find the serial port on the board, which he did. But by that time someone else had already dumped the image and uploaded it. We guess you could say that [Yifan] was shocked by what he found in the disassembly. This a ground-up rewrite compared to past Kindle devices and it seems there’s a lot to be hacked. The bootloader is not locked, but messing around with that is a good way to brick the device. The Javascript, which is the language used for the UI, is not obfuscated and Amazon included many hooks for later plugins. Long story short, hacks for previous Kindles won’t work here, but it should be easy to reverse engineer the software and write new ones.

Gaining access to the device is as easy as injecting some HTML code into the UI. It is then run by the device as root (no kidding!). [Yifan] grabbed an MP3 file, changed its tag information to the HTML attack code, then played the file on the device to exploit the flaw. How long before malicious data from illegally downloaded MP3 files ends up blanking the root file system on one of these?

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Rudolph toy hacked to announce incoming email


Tis the season for hacking, and [Nick McClanahan] at the GadgetGangster is certainly showing off his Christmas spirit with his most recent creation. He had an animatronic Rudolph the Red Nosed Reindeer toy sitting around and thought it would be fun to convert him into an email reading machine.

He tore open the toy, removing its innards, disconnecting the built-in speaker and servos from the original PCB. He then extended wires from those components outside of the body before reassembling the toy. The reindeer is controlled primarily using a Propeller Platform, with an E-Net module and a small audio amp taking care of network communications and audio output, respectively.

Most of the work is done by the software [Nick] is using, which allows Rudolph to periodically check his Gmail inbox for new messages. When the message count increases, the reindeer springs into action, moving and lighting up his nose before announcing the sender’s name.

He’s using a phonemic voice synthesizer for the output, which does the job, though we would go mad if we had to listen to it all day. Since the reindeer is connected to his LAN, it might be feasible to run the data through a more robust voice synth on a PC, returning a better-sounding audio clip for playback.

Check out the video below to see a short clip of Rudolph in action.

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Adding HTTP to Ikea DIODER

[Alex] sent in a neat Ikea DIODER build that controls strings of RGB LEDs with HTTP requests.

We’ve seen Ikea DIODERs controlled wirelessly and over USB, but using the Internet with a DIODER is new to us. For his build, [Alex] used a Nanode, a small Arduino-like board that has built-in web connectivity.

The hardware portion of the build is very simple. A MOSFET controls each LED strip on the DIODER. The stock controller of the DIODER was ditched, meaning [Alex] needed to figure out how to convert an RGB color space to a Hue, Saturation, and Lightness color space “for super-classy fading.” Once that was figured out, [Alex] implemented a 1D Perlin noise function to blend between two colors.

Finally, the great EtherCard library was used to turn HTTP requests into dancing LEDs. [Alex] is thinking about building a JQuery webpage so he won’t have to muck around with entering commands like into a browser. Without a nice web interface, it’s not as futuristic as [Alex] would like, but it’s still cool to us.