Laser Range Finding and File Recovery

In this new years eve episode Jason Appelbaum joins us to talk about Laser Range Finding using the USB Missile Launcher and some custom code. Chris Gerling is in the house doing file recovery the down and dirty way. Trust your Technolust and thanks for a great '08!

Laser Range Finding

Adding laser range finding to the web missile software lets you determine whether a target is in range of the missile launcher. The laser range finding software does work but it is a slightly challenging making it work with the current hardware because the software's so old. It’s really more of a proof of concept than a real tool.

The theory behind it is pretty cool: the distance can be determined by counting the number of pixels from the center of the CCD to where the laser's point is reflected. That count, plus the distance between the laser and the camera, gives us the side of the triangle. Then using some simple trigonometry you can find the base of the triangle which is the distance that the object is from the laser.

The problem is the size of the dot on the CCD is not taken into account, so this theory only works for objects in a certain range. That range depends on the distance between the laser and camera. The missile launcher has a short range so the new idea is using two cameras for the laser range finding, one for the missile launchers short range needs and one for long range playing with the cat. Then you can get the best of both worlds the new concept.

There is also a hardware solution

--Jason Appelbaum

File Recovery with the SIFT

In 418 I demonstrated some of the basics in recovering deleted files. Using a DD image taken from a usb drive which had files deleted from it first, I showed off a program called fls which shows you the inodes for each file on a system. Using these inode references, you can carve out in a filesystem exactly where a given file is supposed to reside in the unallocated space. Darren and I discuss some of the math behind this. In the next part I will be showing an easier method of doing this via foremost.

--Chris Gerling

Until next week we welcome your feedback and remind you to Trust your Technolust