An auto retractable design for a key, like one of those usb flash drives might help. http://www.usbmemorysticks.net/wp-content/gallery/sandisk-cruzer-blade-and

An auto retractable design for a key, like one of those usb flash drives might help. http://www.usbmemorysticks.net/wp-content/gallery/sandisk-cruzer-blade-and-slice/sandisk-cruzer-edge.jpg http://www.usbmemorysticks.net/wp-content/gallery/sandisk-cr... By default, the key will be hidden inside it's case. When the user wishes to open the lock, he can just place the key on the keyhole and start inserting it. :)