Episode 418 — Laser Range Finding and File Recovery
In this new years eve episode Jason 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 would make is so the web user could determine if a target is in range of the missile launcher. The laser range finding software does work but it is a slightly changeling getting it work with current hardware because of the age of the software. It’s really more of a proof of concept than a real tool. The theory behind it, is that distance of the laser can be determined by counting the number of pixels from the center of the CCD to the point lasers reflects on the CDD, 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
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.
Until next week we welcome your feedback and remind you to Trust your Technolust