I have an investor who will pay huge for a device like this for dogs. Obviously a GPS will not fit under the skin because of the battery size and need to be charged. Neither will a GSM modem. I have a solution using Wifi and RFID that will achieve the same results, with the collar being the size of a BIC lighter. Here is the goal: Whenever the dog is stolen, it's location is transmitted, when the collar is removed. This must happen at least once, when the collar is removed. Extra credit for tracking a dog when he runs away. Ideally where he is taken to without wearing his collar. This removal can be detected with RFID or a simple wire that is cut when the collar is cut. Both together. The collar should be small enough so the technologically aware thief will not suspect it has GPS or a modem. Thinking out loud. Thoughts? Ideas?
A smaller version of this to charge AAA size battery? http://www.gizmag.com/npower-peg-uses-motion-to-charge-mobile-devices/10716/