I saw the prototype of one today.A guy brought it here to the keys for mini
season and briefly explained the system to me.
It seemed sensible enough. Customers buy fill cards from dive shop, tanks
inspected and recieve bar code sticker, diver recieves coded fill card.
Aluminum 80's only placed in pull out drawer with steel sleeve, fill collar
aligned.
Card inserted in slot, read, if matches bar code info. tank filled to 3100
while cooled with chilled water.

Looked like it had potential.
Charlie