A toolbox with a built-in (but dismountable) RFID reader and a supply of RFID tags that work with it. Put the tags on your tools and the toolbox will tell you if a tool is present in the box or not. I expect the RFID reader would have a "learn" feature to update its inventory.
If you need to find a tool, dismount the RFID reader and walk about the places you suspect the tool to be and try to find it.-- phoenix, Jan 18 2008 Smart-box Smart-boxThe inspiration for this idea. [phoenix, Jan 18 2008] That's not where that goes Sean. That_27s_20not_20wh...at_20goes_20Sean_2eSimilar, but not the same. [phoenix, Jan 18 2008] Proof of concept http://www.vs.inf.e...w.html?what=toolbox(Apparently it's *real* important for aircraft mechanics to account for all their tools before walking away from the plane.) [DrCurry, Jan 18 2008] Road Test: 2010 Ford Transit Connect http://autos.aol.co...ansit-connect-video"Using an RFID system (radio-frequency identification), your tools get "tagged" and the system checks to see if they're all are within the vehicle. If any of your tools are missing, they show up when you do your inventory, preventing the hassle of leaving without one." [phoenix, Feb 22 2010] Bluetooth finder with cool radar-like GUI on your smart phone http://www.sticknfind.com/Expensive but not more expensive than losing everything all the time [leinypoo13, May 06 2013] Hey, I just said that! But better, all around, than the other idea, and a highly appropriate use of the technology.-- DrCurry, Jan 18 2008 [+] Any sort of flexible, off the shelf RFID kit would be incredibly useful. I spend probably >$1K/yr on replacing things I lose. Thats like 250 euros!-- leinypoo13, Jan 18 2008 i find this to be an excellent idea my friends are mechanics and i know how irritating it is when someone steals or misplaces you're tools-- dexhax, Mar 29 2008 I want one of the right now! I once found my missing 15mm wrench precariously laying in the radiator cross member in my pickup 1 year after I had lost the tool. About once a year i find a socket in the engine bay or on the shop floor that I hadn't seen for quite some time.-- jhomrighaus, Mar 29 2008 [+] I used to work in an industry where we made house calls. It was common for the customers to steal our tools by hiding them in "plain sight". If I didn't know something was missing, I would never ask the customer if he had seen it. Yet if there was something I needed and I said, "Mr. Customer, I had a pair of plyers around here somewhere. Have you seen them?" then he would fess up and either admit that he was "borrowing" it or somehow it mysterously ended up on the coffee table and he would blame it on his kids.-- Jscotty, Jun 18 2008 See link for public service announcemount.-- leinypoo13, May 06 2013 random, halfbakery