Measure heartbeat with smart speakers as sonar


American scientists have added a sonar function to a smart speaker. With high-frequency tones and the sound waves reflected by the body, intelligent algorithms can measure the heartbeat of people in order to detect cardiac arrhythmias without contact. This could be used for in-house or remote diagnosis, for example in rural areas or under quarantine conditions.

The at Nature published Study by scientists at the US University of Washington in Seattle explains that the smart speaker emits a series of high-frequency tones in the frequency range from 18 to 22 kHz for one minute. This is in the upper range of the frequency range that can be heard by humans, which usually extends to 20 kHz in young people.

The microphones of the smart speaker record the sound waves reflected from the patient’s body, which is around half a meter away. The software developed by the researchers themselves calculates the heart rhythm from these signals. According to the scientists, the slightest movements of the upper body and the surface of the skin in the range of 0.3 to 0.8 millimeters are registered. Breathing movements and other disturbances must be filtered out.

The principle is similar to the sonar of a submarine. This sends out sound waves to recognize the environment. The time between the sound signal being emitted and the reflection is measured in order to determine the distance to an object and its direction of movement.

The contactless smart speaker technology was tested in practice on 49 test subjects, half of whom had a healthy heartbeat and the other half had heart disease and irregularities in their heart rhythm. The heartbeat of the test person was first tested by electrocardiography (EKG) and then with the smart speaker. The comparison of the results showed an average deviation of only one or two heartbeats.

The prototype of this smart speaker developed by the US researchers uses seven microphones. Typical smart speakers have between two and seven microphones. The Apple HomePod and Amazon Echo have six or seven microphones. Google Nest devices already use the sonar principle to determine the distance to the user.

According to the scientists, current, widespread smart speakers are therefore almost suitable for use in heartbeat measurement. The sonar principle could possibly even be used to measure blood pressure in the future.


To home page