As shown in the figure below, this circuit uses BP01 type pressure sensor and op amp MAX4472. The BP01 pressure sensor is specially designed for detecting blood pressure and is mainly used in portable electronic blood pressure monitors . It is made of precision thick film ceramic chip and nylon plastic package. It features high linearity, low noise and low external stress. It adopts internal calibration and temperature compensation to improve measurement accuracy, stability and repeatability. The accuracy is ±1% and the zero offset is no more than ±300μV. The MAX4472 is a low-power amplifier chip from MAXIM that integrates four operational amplifiers. In this system, the internal integrated operational amplifier A is connected to a constant current source to provide a constant current for the pressure sensor. The operational amplifier B and the operational amplifier C form an differential input, single-ended output amplification circuit, and directly input ADC0 to monitor the blood pressure DC component. Filtering and amplifying circuit As shown in the figure below, the circuit consists of two parts: filtering and amplification. The MAX267 is an integrated filter produced by MAXIM. It can be used in low-pass, band-pass, high-pass, and other modes. It is flexible and performs much better than the filter circuit composed of integrated op amps. The MAX4471 is a low-power amplifier from MAXIM. The MAX9028 is a low-power comparator from MAXIM. The filter circuit uses the MAX267 to form a bandpass filter (allowing a signal of 0.8 to 38 Hz to pass), filtering out the DC component and power supply in the signal, and the high frequency noise and power frequency interference of the skin and cuff friction, and then further amplified by the MAX4471. Get the voltage signal matched by the microcontroller, enter ADC2, monitor the AC component of blood pressure. At the same time, the signal is converted into a pulse signal by the low-power comparator MAX9028, which triggers the operation of ADC1. Disposable Dressing Change Kit Dressing Change Kit,Wound Dressing Change Kit,Sterile Dressing Change Kit,Disposable Dressing Change Kit Henan Anbang Medical Supplies Co., Ltd. , https://www.anbangmedical.com