One of the amazing things about near-field communication (NFC) technology is that tags don’t need batteries to communicate, and you never need to buy new button batteries for your employee badges because the badge scanner will wirelessly transmit enough power to the badge to verify its legitimacy. Now, chipmaker Infineon wants to make the same thing happen with smart locks that can be powered entirely by the user’s phone.
Infineon is selling a new chip with full details (PDF) to anyone who wants to get in on the idea. It’s called the NAC1080, and it’s designed as a single chip that can do almost everything. It has circuitry that recognizes the user’s NFC phone, gets its power, and drives the smart lock’s motor. It also has embedded security features and a 32-bit ARM Cortex M0 CPU to verify that the user and the user’s phone are allowed to open and close the lock in question.
The manufacturer must provide the antenna, a 3V micro motor and a capacitor to take the place of the battery. A lock like this requires a small charge to be built up before powering the motor but can be done in a matter of seconds. Don’t expect this feature to appear on other smart locks, however. Infineon says the key is the design of the smart mechanical latch that can be opened and closed with very little energy. While Infineon says it can be used for front door locks, it admits that more complex locks have longer response times.
Also, this Infineon technology may depend on what kind of phone you have. Infineon says that in the company’s tests, mainstream phones provide an average of 20mW of energy, but the NFC field strength depends on your phone’s antenna, the lock’s antenna, and how close you can get them when trying to unlock it.