MIT researchers are developing fabric swatches outfitted with sensors, microprocessors, and conductive velcro. The electronic patches can be quickly slapped together to provide different functionality in various form factors.

To make a bag that prevents people forgetting things, the inventors have equipped a module with a radio antenna and receiver. The unit is programmed to listen for signals from radio frequency identification (RFID) tags on objects like mobile phones, keys and wallets.

A sensor module in the bag's handle detects when the bag has been picked up, indicating that the owner might be leaving. This triggers the reader to check through the objects the computer module has been programmed to look for. If it does not detect a required item, it uses a voice synthesiser module in another patch to warn: Mobile phone, yes! Wallet, yes! Keys, no!

As helpful and slightly disturbing as your bag reminding you that you've forgotten your keys is, it could be worse. If you usually transport the detritus of everyday life around in your pockets, having your trousers or jacket remind you about your wallet would be even stranger — New Scientist