Heart Pulse Signal Acquisition The Weft Smart Fabric

In recent years, the intelligent textiles with electronic information become the key point in technology fabric field, in which the micro-electronics technology, information system and computer system are integrated. Generally, the intelligent textiles are composed of three parts: sensors, drivers and controllers. They can collect signals according to the previous setting, and can process and feed back the signals.According to the theories of intelligent textiles with electronic information home and abroad, we study the heartbeat data collection theory systematacially in the thesis, and design a kind of intelligent fabric which can collect the heartbeat signals. We use the intelligent fabric to test the heartbeat, and draw the heartbeat data curve. The experiment data indicates that, the intelligent fabric can collect the heartbeat data and the experiment result achieves the required purpose, and the experiment method is feasible. The designed intelligent fabric includes two parts mainly: the heartbeat data collection system and the weft knitting fabric association.In the data collection system, we use PVDF piezoelectric film sensor to collect heartbeat data, which is sensitive and can collect the heartbeat data exactly, and the PVDF piezoelectric film sensor can be used safely and be used to touch the skin directly; we use the high performance singlechip ADuC824 to process the data, which replaces the three parts in traditional data collection system: data processing, microprocessor and output interface, and it can reach the requirement of data processing, and also the configuration of the system is simple; we can set up the procedure of the chip and its external circuit, and use a MAX232 chip to connect with the computer, and the collected data can be showed on the computer directly.In the selection of the weft knitting fabric, we use a columniform model which is approach to chest circumference to test the fabric tension, and place a spring between the fabric and the model to test the fabric pressure according to the reciprocity of the strength. By the comparison of the pressure which is made from the formula, we can know that the pressure tested by the columniform model can reach the testing target.In the thesis, we use different knitting fabric to combine with the data collection system and use the intelligent fabrics to collect the heartbeat data. According the testing result we know that the designed data collection system can collect the heartbeat data exactly. In the quiet state, when different fabrics have the sameelongation, the initial value and maximum value of the testing data are increased along with the increase of the fabric tension; when the same fabric has different elongation, the minimum value and maximum value of the testing data are also increased along with the increase of the fabric tension; in the athletic state, the collection frequency of the testing system is increased, and the initial value and maximum value are also increased with the same elongation of the knitting fabric.The research theory, the experiment method and the experiment result of the thesis can provide important value of theory and practice for the follow-up research of intelligent textiles. The designed intelligent fabric is a rough model, and it need to improve and perfect further.