Flexible Sensor for Measurement of Skin Pressure and Temperature for the Prevention of Pressure Ulcers

With the prolonged lifespan of the average person, the number of hospital stays have increased. Currently, pressure ulcers are one of the most severe complications associated with prolonged hospital stay. The protocol in today€™s hospital is to rotate bedridden patients once every two hours to prevent pressure ulcers. This puts a strain on attending nurses as the risk of a pressure ulcer for a patient is not universal and therefore, a universal preventative protocol is not the most effective solution. This thesis describes the circuit design and physical implementation of a device to address the issue of pressure ulcers. The device has the form factor of a patch to be placed on specific, at risk areas of the human body. The device was designed and prototyped first on a rigid structure and then on a flexible printed circuit board substrate. A calibration procedure was developed to reduce part to part variability inherent to the pressure sensor. The resistance measurement was achieved through a novel approach including the use of a timer removing the need for an analog-to-digital converter. A seven hour experiment was conducted with live, animal subjects to measure the pressure and temperature of at risk areas of the body. The results of the experiment successfully prove the fundamental approach outlined in this thesis and justify continued research and refinement into the product design