A Norwegian developer has created Doorbl, an app that uses NFC tags and QR codes to offer homeowners a way to communicate with visitors when they aren't at home or instantly able to come to the front door.

"My girlfriend was home on parental leave and several mornings, when she was busy taking care of our son, someone rang the doorbell," Doorbl developer Roy Solberg explained to NFC World. "By the time she was finished, whoever rang the doorbell was long gone.

"So she said that there had to be some way to get in contact with the person outside telling them to just hang on for a minute or leave the package outside or whatever. This led me to think about using NFC for a quick establishment of the connection between the person outside and the person inside."

"Today most of us have our cell phones within reach all day, so using an NFC tag is a much cheaper and simpler way to solve the initial problem rather than installing some expensive new hardware at the door."

To use the system, homeowners simply register on the Doorbl website and then order either an NFC tag with the URL of their doorbell stored on it, or a label printed with a QR code containing the same information, and attach it to their door.

When a visitor taps or scans the doorbell tag, a push notification with their name and phone number is then sent to the owner's mobile phone. The owner can then respond via an SMS message or phone call.

Doorbl is currently available as Android and iOS apps that enable users to pre-fill their contact details so that, when they tap or scan a Doorbl tag, the app will automatically open and they can simply add a short text message before 'ringing' the doorbell. Owners of other phones can also use the service, but need to complete their contact information in full each time.