While browsing Instructables the other day I found this brilliant idea- https://www.instructables.com/id/Top-secret-Control-a-hidden-usb-port-with-a-magnet/ - Upon looking at the comments, I found that it is possible to lock a USB port by putting a switch on one of the data cables. While it is an awesome idea, I found one major flaw; if someone was trying to read, say a flash drive, they could simply plug it into a different, non-magnetically locked port. My solution to that is to lock the flash drive itself. The following is instructions on how to lock the drive using the same magnetic switch technique, but with only one reed switch.
Step 1: Prepare the Flash Drive
First, obviously, get a flash drive. One of the swivel types works well, that's what I used. Here's an example of one, a bit overpriced though. http://www.dx.com/p/ourspop-u019-swivel-usb-2-0-flash-drive-red-sliver-4gb-286491#.VDc3S0PD8b1. Remove the metal swiveling jacket thing, its pretty easy, just pop it off. Next, gently pry apart the case, a knife and small flat head screwdriver helps very much. The inside should look like picture four.
Step 2: Get the Other Stuff
The only extra parts are the reed switch- http://www.taydaelectronics.com/electromechanical/switches-key-pad/reed-switch/fr2s1020-reed-switch-1-5a-10-20-a-t-spst-no-200-vdc-vac-fr2s1020-0520.html - and a short piece of wire.
Step 3: Make It Lockable
To add the reed switch, simply desolder one of the data pins (the two center pins coming off the USB connector) and solder one side of the reed switch to the board in place of the data pin. Next solder the wire onto the data pin on the USB connector. Last, solder the other end of the reed switch to the wire coming from the data pin. You might want to plug it into the computer at this point to test it. First plug it in, the computer should know at something is plugged in, but not be able to recognize it. Then take it out, place a small magnet on top of the switch, and stick it back in. It should operate normally now. If it works correctly, move on to the last step, if not, recheck the connections.
Step 4: Put It Back Together
The last thing you need to do is gently put the two halves of the case back together, with the new magnetically locked flash drive board inside. Then put the metal swiveling jacket thing back on. Now it's done. Go find something super secret to store on it, just use a magnet to unlock it. Comment if you have any improvements or suggestions, or if you built one. Thanks for reading!
P.S. please vote for me in the tech contest.