New temperature sensor runs on 'near-zero-power'

Scientists have developed a tiny temperature sensor that runs on "near-zero-power" and could extend the battery life of wearable devices that monitor health, as well as Internet of Things and smart home systems.

The sensor, developed by researchers at the University of California, San Diego in the US, runs on only 113 picowatts of power - 628 times lower power than the state of the art and about 10 billion times smaller than a watt.

It could extend the battery life of wearable or implantable devices that monitor body temperature, smart home monitoring systems, Internet of Things devices and environmental monitoring systems.

The technology could also enable a new class of devices that can be powered by harvesting energy from low-power sources, such as the body or the surrounding environment, researchers said.

"Our vision is to make wearable devices that are so unobtrusive, so invisible that users are virtually unaware that they're wearing their wearables," said Patrick Mercier, a professor at UC San Diego.

"Our new near-zero-power technology could one day eliminate the need to ever change or recharge a battery," said Mercier.

"We're building systems that have such low power requirements that they could potentially run for years on just a tiny battery," said Hui Wang, a PhD student at Mercier's lab.

The temperature sensor is integrated into a small chip measuring 0.15 square millimetres in area. It operates at temperatures ranging from minus 20 degrees Celsius to 40 degrees Celsius.

Its performance is fairly comparable to that of the state of the art even at near-zero-power, researchers said.

One tradeoff is that the sensor has a response time of approximately one temperature update per second, which is slightly slower than existing temperature sensors.

However, this response time is sufficient for devices that operate in the human body, homes and other environments where temperature do not fluctuate rapidly, researchers said.

Moving forward, the team is working to improve the accuracy of the temperature sensor. The team is also optimising the design so that it can be successfully integrated into commercial devices.