A device has a flexible substrate supporting an array of magnetic sensors exposed to a uniform external magnetic field. One or more controllers receive magnetic sensor signals from the magnetic sensors. The one or more controllers collect reference magnetic sensor signals when the flexible substrate is aligned with the uniform external magnetic field. The one or more controllers collect first polarity magnetic sensor signals in response to deformation of the flexible substrate in a first direction. The one or more controllers collect second polarity magnetic sensor signals in response to deformation of the flexible substrate in a second direction. The magnetic sensor signals establish a profile of the orientation of the flexible substrate with respect to the uniform external magnetic field.