Wireless charging would be a solution for our travelling-charger-forgot-pin-different problem.
Even, Students used to ask me to do a project for wireless charging of a mobile battery. But i had denied them that its not possible as it would be highly energy inefficient and the solution would take huge space and include a lot of power loss. But here is some good news, TI has now made it possible. They say "Start designing a world without cords". Yes, TI has launched a range of Wireless power solutions which include Wireless energy transmitter and receiver solutions. They call them the bqTesla family of transmitter and receivers. The Charger and the battery device are magnetically coupled and the Charger device can adjust the power output automatically depending on the feedback messages or error messages received wirelessly from the battery device. The transmitter coil is powered down always and only is enabled when a receiver or a battery device which needs charging is brought near the transmitter. This helps since most of the time we forgot to turn off our battery charger after unplugging it from our handset. This solution solves this problem too as it automatically detects the handset taken away from it and turns off itself. Isn't it smart. :)