24 May 2016
Engineers from the University of California San-Diego have made a first step towards the goal of building a science fiction tricorder.
Normally, wearable devices are only capable of measuring one specific signal at a time, such as heart rate or blood pressure. Measuring multiple signals simultaneously is a requirement of any all-purpose device. The Chem-phys patch from UC San Diego is something of a first not just due to it measuring two signals simultaneously, but because it monitors lactate, (a biochemical product of physical effort) something that few commercially available devices measure. The device could have a number of applications, from monitoring patients with heart disease to helping athletes improve their performance.
It uses two sensors, one for measuring heart rate using EKG electrodes, and the other for measuring lactate in human sweat.
The problem wearable devices encounter with measuring multiple signals is one of miniaturisation. Squeezing multiple sensors into a small area can cause interference when the signals get short-circuited. The team encountered this pro blem, finding that sweat disrupted the EKG electrodes but were able to overcome it by adding a layer of silicone, insulating them.
Taking the form of a flexible patch, the sensor is wired into a small circuit board which includes a Bluetooth chip, allowing it to transmit its results wirelessly to a computer or smartphone.
After testing, the results were comparable to commercial heart rate monitors, whilst lactate measurements matched data previously collected from exercise studies. For their next step, the team hopes to develop their system further, adding sensors to test for other biochemical products, and standard vital signs.