Can you build a key charger?

[GuidoK]

Maybe you can put the key next to the phone while it charges and the key can steal some of that induction fields away 8)

 

[ph001]

What I need now is for some kind soul to send me the innards of a key (pickup coil and battery are the only real important bits). I'll then wind a small air-cored choke and run it with a 125KHz oscillator and monitor the charge into the 3V lithium cell.