There are a couple different ways that someone could tamper with a smart lock. One of these is to attempt to access the internals of the device by removing the outer shell to trick the device into opening. In this case, switches can be used to determine when the shell has been removed or bent out of position. This implementation is described in the Limit Detection for Tamper and End-of-Travel Detection Using Hall-Effect Sensors application brief. If the smart lock uses Hall-effect sensors to determine the position of the magnet, someone could try to trick the sensor by using a large magnet to trigger the sensor. One way of eliminating this risk is to have an additional sensor that alerts the main controller of the smart lock when a magnetic field stronger than the design accounts for is present in the system. The additional sensor implementation is also shown in the Contactless, Hall-Effect Variable-Speed Trigger Reference Design With External Field Protection design guide.