Fig. 4: Pressure monitoring and alarming feedback for posture change.

A Photographs of a subject in different postures. B–D Photographs of the devices at each location and G–I the continuous monitoring of B sacrum, C left heel, and D right heel pressure. E Photographs of an accelerometer attached to the lower stomach, and J the acceleration data associated with posture changes of the subject. F Photograph of a satellite unit designed to alert the average pressure level and the time duration without posture changes, as well as K alarm level (Time stage, and Pressure level) associated with the pressure monitoring.