New-TechEurope Magazine | November 2017 | Digital Edition

Sensors Special Edition

the systolic pressure. As the cuff’s pressure reduces the medical professional will no longer be able to detect audibly the flow of blood in the artery; the diastolic pressure. Using MEMS-based sensors, non- invasive blood pressure monitoring can be largely automated and it is one of the biggest applications by volume for MEMS pressure sensors. Silicon Microstructures is a leader in the design and manufacture of MEMS pressure sensors and the SM4421 is a good example of such a pressure sensor used in this application. Housed in a SOIC-16 package it integrates a MEMS sensing element and signal conditioning ASIC to provide a 14- bit temperature-compensated output through an I2C interface. Available in gauge, differential and asymmetric configurations, the devices that make up SM4x21 series can operate across a pressure range from 2.5PSI to 14.9PSI and can be used in a range of different medical applications. The Future of MEMS in the Medical Sector MEMS has the potential to transform many aspects of medical care; the concept of a lab-on-a-chip will lead to fast and low cost diagnosis in remote locations and developing countries becoming a reality. The technologies used to manufacture MEMS devices are also employed in the development of nanotechnology and the two are closely related. This will see the sciences of microfluidics further merging with microelectronics, while the introduction of new materials such as carbon nanotubes and graphene offers even greater potential.

Figure 2: The EVAL-ADXL362-ARDZ

Figure 3: A block diagram of the ICM-20948 9-axis MEMS motion tracking multi chip module

well as drug infusion pumps. They are also instrumental in continuous positive airway pressure devices for treating sleep apnea, and in negative pressure wound therapy. Non-invasive blood pressuremonitoring is used to measure a patient’s systolic

and diastolic blood pressure via the largely familiar inflating arm cuff. Pressure is applied to the arm until the artery is occluded, at which point the blood stops flowing. Pressure is released until blood starts flowing (normally detected audibly), giving

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