The 3mm thick aluminium Ping card holder connects to iOS and Android phones (with Bluetooth 4.0 capability) and sends an alert reminding the user to put their card back in the wallet after each use.
The wallet also has a built-in speaker which beeps if someone takes it or the user's phone. If the wallet and phone lose connection, Ping not only sends out an alert but records the last known GPS location.
The wallet has a range of about 100 feet and the battery lasts for up to two years, after which it needs to be replaced for a "very small fee".
Having built working prototypes the inventors have taken to KickStarter to raise funds for full production, so far raising around $8,700 of their $30,000 target. When it goes on sale it will retail for $79.