This Thanko Mailbox Sentry notifies you when a piece of mail has been deposited in your postbox. It maintains a running count too, rather like the ‘you’ve got mail’ feature on email, only this time with real letters and packages. We can see it being very useful for folk who live on the top floor of their apartment who can check to see if the money has arrived without travelling from the couch. $95.00.

 Known as the Posto no Mihariban in Japan, all you have to do is set up the antenna and transmitter on the inside of the lid of your post box. When something is put inside by the mailman it sends out a signal to your receiver, connected up to 100m away in your home.