Researchers at MIT have developed three "smart wallets" equipped with technology to help you stay on budget.
The wallets, which are linked up to bank accounts, aim to make shoppers more aware of their finances every time they swipe a credit card or spend money.
The Mother Bear wallet is created so it's difficult to open when a bank account is low. The resistance increases as a given budget threshold is approached.
This wallet design uses a passive circuit at its heart. A hinge is made out of a motor that can be shorted, and the two leaves of the hinge are sown into the sides of a wallet. When the motor is shorted with a small switch, the hinge offers more resistance, making the wallet harder to open or close.
Another wallet style -- The Peacock -- appears to grow and shrink to reflect the user's account balance. The effect aims to give users a feel a subtle tightness or looseness in their pocket that persists until their account balance changes.
This wallet uses a mechanical servo embedded in a wallet, which is a small device controlled by a square wave of varying frequency to rotate its arm from parallel to perpendicular to the wallet surface.
The final wallet, The Bumblebee, buzzes whenever the bank processes a transaction from the user’s account. This encourages a conscious, de-virtualized connection between the user handing over a credit card and money sitting in a bank account. A buzzing that doesn't have an associated purchase also alerts the user to fraud, or when a borrowed card is being used.
The Bumblebee wallet uses a vibrator motor in a wallet pocket to generate vibration feedback. It picks up transaction information via Bluetooth from an Internet-connected cell phone or computer. The intensity of the vibration correlates to the amount of the transaction.
The wallets are expected to be available for purchase in the near future.