This is part of Smart Lock which is one of the coolest things in Lollipop.
Add a trusted device to keep this device unlocked when connected
That’s how Google describes is, and is pretty much what it does and how it works.
Will focus on Bluetooth now since it’s what most people got, and it’s the easiest way of doing this. I will use my desktop computer as a trusted device, I would use a smartwatch as it if I had one…
First you need to make sure that Smart lock is active
- Enable a lock screen (pin/pattern/password) under Settings > Security > Lock screen
- If there is no Smart Lock even with the correct lockscreeen set, you need to follow THIS
If you already got a paired and connected bluetooth device
Settings > Security > Smart lock, where you select Trusted devices. Tap Add trusted device on the bottom of the screen that shows up. Select device type, Bluetooth in my case. Select the connected bluetooth device. And, that’s it.
If the bluetooth device you want to use is not paired and connected
Settings > Bluetooth, where you turn it on and scan for devices. Make sure that the bluetooth device you’re pairing with is in pairing mode. That depends on the device used, and I will not cover that here.
When the device is paired and connected, you will see an unlocked pad lock icon in the notification field that asks you if you want to add the newly connected device as a Trusted device.
Ok, done all that. How do I know that it works?
The only really tell is that the pad lock on the lockscreen it unlocked. Now when you’re in reach and connected with the bluetooth device, the padlock will unlock and let you just swipe the lockscreen open. If you’re outside it’s reach, you need to enter you pin/password/pattern.