Sensing systems can include magnetoresistive sensors suitable for both angle and field strength sensing. The system can include one or more magnetoresistive sensors that can sense one or more aspects or characteristics of a magnetic field. The system can include a first magnetoresistive sensor that is configured to sense the magnetic field angle or rotation and a second sensor configured to sense the strength or magnitude of the magnetic field. The system can determine an operation state of the system based on the sensed characteristic(s) of the magnetic field. For example, if the system determines that the sensed magnetic field strength is below a threshold value, the system can determine that it may be operating in an error state. In this example, the system can generate an alarm signal based on the determined error state.