It’s said that simplicity is the ultimate in sophistication, and a new iPhone app called Knock definitely lives up to that: it lets you unlock your Mac by simply knocking your iPhone twice.
Knock comprises two applications: one that runs silently on your iPhone to transmit knocks, and another that sits on your Mac to receive them. Neither has any complicated interface or setup procedure. In fact, once you’ve purchased Knock on your iPhone (R32.99) and run it for the first time, it prompts you to download and run the Mac app. Neither is a large download, either.
After pairing your iPhone with your Mac, using Bluetooth, the link is established and the app configures itself.
It’s all made possible through Bluetooth 4.0 Low Energy. This version of Bluetooth supports an energy state where it doesn’t drain battery power unnecessarily, and the handshake procedure to unlock a Mac is quick – though it takes a few seconds to pair when resuming from sleep.
It’s also a requirement that your iPhone and Mac both have Bluetooth 4.0 LE, thus supported Macs and phones are limited to more recent models.
