Disappearing sensor : Textile based sensor for monitoring breathing

The monitoring and interpretation of respiration pattern plays an important role for the early detection and the prevention of serious illness, such as asthma, sleeping apnea, bronchitis, and lung cancer. In this interdisciplinary project a system based on a smart shirt with integrated textile sensor for personal respiratory monitoring was developed. Due to the fact that textile products are flexible, washable and bring no discomfort to wearers, the smart shirtis an excellent interface for performing long term respiratory monitoring in real life situations outside the clinic. Two stripe liked sensors located on the chest and abdomen position respectively were integrated in a smart shirt. The sensors were made by coating with conductive silicone on the fabric surface of the smart shirt. Conductive silicone reflects compression or extension by resistance change and in this application resistance change can be utilized to indicate the respiratory pattern of the wearer. A prototype system was made to record the resistance change in real time and transmission to a PC or PDA for further processing. Snap button and conductive threads were used as the interface and transmission wires between the smart shirt and the recording system. To verify the performance, test were made with 10 subjects, whose spontaneous respiratory patterns were recorded during sitting still, walking and jogging. In addition, a number of abnormal respiratory conditions, such as deep breathing, hyperventilation and sleeping apnea were simulated. The results show the smart shirt performed in a very good manner, the system can sense and record the person's breathing during normal daily activities. The sleeping apnea simulation indicates potential application in diagnosis and clinical treatment. The smart shirt is soft and comfortable to use and enables long-term monitoring to be performed outside the laboratory