Portable Blood Pressure Monitor
More and more people are suffering from hypertension which has become a common disease in the world today. People use blood pressure monitors to see if their arterial pressure is within a normal range. There are two types of blood pressure monitors at present, mercury and electronic types. Electronic blood pressure monitors have advantages of inflating, deflating and showing alphanumeric result automatically, which the traditional mercury ones do not have. Portable blood pressure monitors belong to electronic type and feature small size, low weight, and ease of carry for examining anytime.
A portable blood pressure monitor is typically made up of a pressure sensor, a pump, a valve, a cuff, a MCU, a LCD display, a power management, and other functional parts (USB interface, buttons and buzzer). During inflation or deflation process, pressure sensor converts the pressure in cuff chamber to electric signals, which then are filtered, amplified and transmitted into MCU for A/D conversion and calculating systolic and diastolic pressures, as well as pulse rate based on oscillometric method. The results are finally displayed on LCD. Pump and valve are low-power mechanisms and thus can be driven respectively by two MOSFETs under the control of MCU. Portable blood pressure monitors use battery as power supply and integrate a power management consisting of a DC-DC converter and a LDO. The latest wrist monitors boast an accelerometer to determine height difference between wrist and heart so as to obtain a more accurate result.
Today, wrist blood pressure monitors have become dominant in family healthcare market because they are smaller and thus easier to carry compared with arm portable monitors. Generally, portable blood pressure monitors have been the ideal healthcare instruments for families and are getting widespread around the globe.