Beyond watches or specialized headphones, Google has imagined a technology allowing heart rate to be measured with any active noise reduction earphone.
To measure a user’s heart rate, connected watches and bracelets currently all use the same technology: photoplethysmography. Concretely, this system will make it possible, thanks to the emission of pulsations of green light, to analyze the rate of light reflected by the blood and to conclude the user’s heart rate.
This system nevertheless presents two concerns to be generalized. First, it is necessary to prevent light leaks from or to the outside, at the risk of distorting the measurements. Then, this system is necessarily bulky, since it is necessary to place both light sensors and emissive diodes in the watch.
While there are indeed several models of wireless headphones that offer heart rate analysis – we think of the Anker Soundcore Liberty 4 or the Amazfit PowerBuds Pro – these are headphones designed specifically to analyze heart rate. cardiac.
A complicated name for a simple principle
For its part, Google would like to go further as reported by the site 9to5Google. In a research article, Google has indeed set about working on another system to measure the heart rate of users of wireless headphones, without adding components to the headphones in question.
Google has developed a system called audioplethysmography (APG). In other words, instead of light waves, sound waves are supposed to inform the headphones about heart rate:
The APG sends a low-intensity ultrasound signal through the speaker of a noise-canceling earphone and records the echo in the microphones inside. We observed that the volume of the ear canal changes slightly during the deformation of the blood vessels and that the pulse will modulate these ultrasound echoes. We designed mathematical models to analyze the underlying physics and provide an APG signal to determine heart rate and heart rate variability.
The advantage of this technology is that it only uses components present in wireless noise reduction headphones, equipped with both a speaker (the transducer) and microphones positioned at the entrance to the conduit auditory to analyze residual sounds.
For the moment, Google is not yet talking about putting this technology into practice and the article is content to highlight the fundamental research around APG. However, given the significant weight of the manufacturer in the field of wireless audio – it notably offers numerous functions to third-party manufacturers via Fast Pair – we can easily imagine the arrival of this functionality in the medium or long term, too. of course on Pixel Buds headphones than on models from other brands.