Wireless Arduino cat food dispenser

posted by Gerrit Coetzee

Reader, [Andres Leon], has two adorable cats with very specific dietary needs. Instead of altering his schedule, he donned his hacking hat and designed a very solid cat food dispenser. The dispenser consists of a rotating drum with a slot in it and a PVC pipe Y-fitting to distribute the food evenly. The brains of the machine is an Arduino Deumillanove and an XBee module. The unit can be controlled by a web interface or it can run completely standalone. [Andres] ran into a problem where the drum’s resistance to turning varied based on how much food was inside. He solved this with a clever laser position indicator. A piece of plywood is lined up with the slot at the top so that whenever the slot is facing up it keeps the laser from shining on a photoresistor. The cats were afraid of the servo noise at first, but now they run to their bowls whenever they hear it.

Lazy man’s USB RFID reader

Posted by Caleb Kraft

[Don] had some Serial RFID readers that he needed to work and be powered by USB. He went out and purchased a simple serial to USB converter, but was left with the problem of the operating voltage. He supplies the schematics on his site for his solution. Basically he gutted the converter and integrated it all with the appropriate voltage broken out. The final project is nice, using the serial to USB convert as the project box and even including a nice LED to show when an RFID tag has been read.

Various Cantenna builds

posted by Steve Watkins

Here is a classic project used to increase wireless signal strength. Cantennas focus using a waveguide very much like a magnifying glass focuses light. [Robert] made a Natural Light beer cantenna, pictured in the upper left. His approach used three beer cans, a paper towel holder, and a shower curtain rod. On the tipline, he noted a signal boost from 11Mbps to 54Mbps. This is certainly something we can hack together if our room lacks adequate signal. Read about parabolic and seeking versions after the break.

Homemade regenerative tube radio

posted by Steve Watkins

There are no microcontrollers in this project. In fact you wont find a single transistor. This classic regenerative tube radio, modeled after an early 20th century homebrew is complete with schematic and additional photos. For those who are not familiar with tube designs and for simplicity, the regeneration circuit can be thought of as feedback though this relation may be argued. Read the rest after the break which includes a crash course in tube operation

Building a Snorricam

posted by Caleb Kraft

With digital cameras getting cheaper and higher quality, we find ourselves more capable of using them to make videos. A Snorricam can be a very useful tool if you like the effect it produces. This specific design allows for adjustment of the height and angle of the camera allowing for even more possibillities. As you can see in the video after the break, it seems to work pretty well. It might be nice to add some kind of vibration absorbtion though. Anyone got any ideas on that?

Live Android

posted by Caleb Kraft

Excited about google Chrome? Can’t wait? Why not play with google’s other OS, Android. You can now run Android from a live cd on any X86 computer. Just pop it in and go without any damage to your existing data. They’ve already gotten it working on the EEE_701, let’s see one with touch screen installed.

Binary reversing comic

posted by Zach Banks

For day two of Black Hat, we sat in on on [Joe Grand], [Jacob Appelbaum], and [Chris Tarnovsky]’s study of the electronic parking meter industry. They decided to study parking meters because they are available everywhere, but rarely considered from a security perspective.

Binary reversing comic

posted by Zach Banks
filed under: cons, downloads hacks, security hacks

Last month, in preparation for Defcon 17, the qualifiers were held for capture the flag, one of Defcon’s most well known events. One participant, [mongii], did a writeup on how to solve problem B300. The challenge was to find the decryption key used by a program that had several twists that hindered debugging. After grappling with self-modifying code and junk instructions, the team was finally able to find the answer. This win helped Sapheads place in the top 10. Over at xchng.info, they are collecting solutions to the other problems. Sadly, they’re not all in comic form.