Blood Pressure Sensor – Working and It’s Applications

Blood Pressure (BP) is one of the important vital signs. It is the pressure exerted by the circulating blood on the walls of blood vessels. Blood Pressure is expressed as the ratio of the systolic pressure over diastolic pressure. Mercury sphygmomanometer is being used for measuring blood pressure. In this, the height of the column of mercury is considered for measuring the blood pressure. The oscillometric method is used for automated blood pressure measurements since 1981. With the advance in technology devices for measuring blood pressure through the non-invasive oscillometric method are being developed. One such device is the Blood Pressure Sensor.

What is a Blood Pressure Sensor?

Blood Pressure can be measured both by invasive and non-invasive methods. In the non-invasive method, no piercing is required and is easy to use. Blood Pressure Sensor is used to measure the blood pressure using the non-invasive method. It is similar to sphygmomanometer but instead of the mercury column, a pressure sensor is used to detect the blood pressure.

Working Principle

Usually, pressure cuff linked to a mercury column is used to measure the blood pressure. Here, the doctor manually pumps the cuff to increase the pressure on the artery. Then using stethoscope the noise of the blood rushing through the artery.


In automatic Blood Pressure measurement system, instead of mercury a pressure sensor is used to detect the pressure in the artery and give output. This digital output is displayed on the monitor. This monitor has an onboard processor to process the output given by pressure sensor, record results and display them on the digital read-out screen.


Being non-invasive, this Sensor is safe to use. It is easier to use and can be monitored by any individual. Instead of watching the mercury levels and calculating pressure, this sensor makes the task easier by giving results automatically.

Applications of Blood Pressure Sensor

This sensor is very important for High Blood Pressure patients, as it is also available as ‘at-home’ solid-state Blood Pressure Monitor. This system is portable. It is easy to carry and operate and highly useful in remote areas where medical facilities are not available.

The main sensing element of this system is the pressure sensor present in the chuff. For an accurate and reliable measurement, this pressure sensor should be carefully selected.

Honeywell’s 26 PC SMT pressure sensor is one of the examples of pressure sensors used in this system. This sensor is small, low-cost and can measure higher values of pressure. This sensor is used directly with the printed circuit board and can measure pressure faster and more accurately. As the sensor provides true surface mount capability, true installation cost of this sensor is very low.

Using Oscillometric techniques this Sensor can measure systolic, diastolic, and mean arterial pressure. It can also measure the pulse rate. This automated system can be connected to the main power or used with batteries. What ratio of the systolic pressure over diastolic pressure is considered to be the normal blood pressure?