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Researchers at Cornell University have found a way to measure a variety of vital signs, including breathing frequency, blood pressure, heart beat by analysing the way radio waves get distorted as they flow through moving organs (which is the case with the heart, lungs and blood vessels).
The method is based on RFID (Radio Frequency IDentification) tags. These can be passive or active (passive tags do not have internal energy source and work by scavenging on the electromagnetic field used by the reading device, active tags have a battery powering them). The reading device emits a low power electromagnetic field that permeates the environment. This field gets distorted by movement, such as the one of our internal organs. These distortions are captured by the RFID that works like a sensor (using its antenna) through a process called “near-field coherent sensing”. The reading device gets the information from two RFID placed on the waist and wrist areas of a person and a software decodes the distortions into information (the software converts the distortion into blood pressure, hearth beats and so on). The passive RFID can even be woven in a garment, like a shirt.
Basically, everything that moves creates a distortion, including bowels movement, and the distortion can be traced back to the cause. The use of an active RFID, may be placed in a pocket, makes the measurement even more accurate.
What is also amazing is that with this method it is possible to monitor hundreds of people at the same time, like those waiting in a crowded emergency ward. Each person is given an RFID and this has a unique code that gets associated to the signals transmitted from the RFID tag to the receiver. This makes it possible to distinguish between more than 200 hundred sources.
The researchers are experimenting with tags embroidered in clothes using nanoparticle to create the RFID tags and the antennas. The idea is to create a wearable sensor, practical to wear, that can provide data to the smartphone of that person, thus ensuring a continuous monitoring of several vial parameters.
