If you have a Mi Band and you've wanted to use your Mi Band as a Trusted Device with Android's SmartLock feature, you may have learned that SmartLock won't let you add the Mi Band as a Trusted Device. In fact, your Mi Band might not even show up as a device that SmartLock will let you select.
The solution, I've found, comes with the help of a free app called nRF Master Control Panel. The nRF Master Control Panel app can help make your Mi Band visible as a device you can select with Android's SmartLock feature.
The tutorial is in the short video here. Watch it, follow the simple steps, and see if this will help you use your Mi Band as a SmartLock Trusted Device.