Bluetooth redefines ubiquitous. It's seemingly everywhere, and nowhere more so than in personal wearable devices such as fitness trackers, smart watches, audio headsets, earphones… you name it.
But what if it's not the best technology for the job? Researchers at the University of California, San Diego in the US have developed a prototype to show off a new wireless communication technique which they say massively outperforms existing wireless tech by using the human body itself to help send data between devices.
The researchers call their new method "magnetic field human body communication". The technique uses the body as a vehicle to deliver magnetic energy between wearable electronic gadgets. For the system to function and propagate magnetic fields through the body, the wearable device needs to be circular in nature (like the coil shown in the image above), meaning it could work for things like fitness bands, smart watches, headbands, or belts.
Why would we do this? The primary benefit is lower power consumption. Whereas Bluetooth devices worn on the body transmit data via radio signals, the electromagnetic radiation that makes up these signals is blocked by something – you. Yep, our bodies get in the way of the data transmissions, creating obstructions and resulting in 'path loss', which can only be circumvented by boosting the device's power.
The end result is that Bluetooth devices aren't very power efficient when we wear them – something you're more than likely to have had personal experience with – and it's a problem that's only compounded by the fact that most wearable Bluetooth gadgets are small and light, meaning they only have very small batteries in the first place.
By sending data via magnetic fields directly through our bodies, however, path loss can be cut down by a huge amount. The researchers say path loss using magnetic field human body communication is more than 10 million times lower than that of Bluetooth radios.
"This technique, to our knowledge, achieves the lowest path losses out of any wireless human body communication system that's been demonstrated so far," said Patrick Mercier, lead author of the study, in a statement. "This technique will allow us to build much lower power wearable devices."
If you're concerned about whether sending magnetic energy through your body is a good idea, the researchers say you have nothing to worry about. They say that ultra-low-power communication systems in wearable devices will transmit signals of much less power than things like MRI scanners and wireless implant devices, with magnetic fields passing freely and harmlessly through biological tissue.
Another advantage of the technology could be security. Compared to something like Bluetooth, which transmits data in a wide radius of several metres, magnetic field human body communication prevents any kind of digital eavesdropping, as the signals are largely contained to your body. The researchers say information is neither radiated off your body, nor can it be transmitted from one person to another.
While this means the method won't be suitable for sending data from wearable devices to remote gadgets (such as audio speakers or a computer), for personalised applications, some people may find the limitation is actually a positive. "Increased privacy is desirable when you're using your wearable devices to transmit information about your health," said Jiwoong Park, first author of the study.
The researchers presented their study at the 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society in Milan, Italy.