SMD(Simple Magnetic Detector) is a magnetic field detection tool for Apple Watch.
- Monitor the X, Y, and Z components of the magnetic field with the detailed sensor view.
- Customize sensitivity and notification interval settings to suit your preferences.
- Get notifications when significant changes in magnetic field strength are detected.
- Polarity-specific haptic feedback

In terms of Apple Watch usage, there may be issues with notifications not being triggered due to the device being suspended as a result of wrist tilt or the passage of time. However, in Analog Watch Mode, the device is less likely to be suspended and, even if it does, it will become active again simply by tilting the wrist. Analog Watch Mode is recommended for optimal performance.