ANU researchers on track to designing energy-harvesting wireless sensors

The Australian National University (ANU) has taken the first step into determining the feasibility of developing prototype wireless sensors powered by harvesting renewable energy from an ambient environment to be used in industries such as healthcare and agriculture.

Dr Salman Durrani, lead researcher from the ANU Research School of Engineering, explained to ZDNet that the initial research identified it possible to replace battery-operated sensors with energy harvested from solar or radio frequency sources such as communication towers and other telecommunications technology.

Durrani said that while wireless sensors are increasingly being used, these sensors are battery-operated, which is an increasing problem because it requires the need to be frequently replaced.

"If we can develop battery-less sensors and instead have sensors powered by energy harvesting from the ambient environment then we will solve a major problem," he said.

He noted, however, the idea of harvesting power from radio, television, and other telecommunications is not a new idea.

According to Durrani, the main challenge the team was trying to solve was the amount of energy that can be harvested. He said currently, a typical high resolution sensor can harvest approximately 10 milliwatts, which comparative to a typical smartphone that requires 1 watt of power, is very small.

"The main challenge becomes how can you reliably power a device that has no battery because if a device is harvesting energy, it first needs to wait before it has harvested sufficient energy before it can communicate," he said.

"Imagine a sensor that's powered from energy harvesting, and it has to wait a few days before it can harvest enough energy to communicate, and if the sensor is monitoring bushfires or a critical event, then that information will never get conveyed because the delay in the communication is very large.

"What we have looked at in our research -- is it possible have realistically small delays and determine the feasibility of powering small low power wireless sensors using energy harvesting."

He said the team went about solving the problem by modelling how much energy it took to sense and transfer information by wireless sensors.

Durrani said the research dealt with an important practical problem, given wireless sensors are being used, for example, in viticulture to measure temperature, wind speed, light, humidity, and soil moisture, as well as in sports to collect performance data.

"If we can use energy harvesting to solve the battery replacement problem for wireless sensors, we can implement long-lasting monitoring devices for health, agriculture, mining, wildlife, and critical national infrastructure, which will improve the quality of life," he said.

Looking ahead, Durrani said there are plans underway to develop prototype sensors, which could be potentially deployed in a smart home to monitor temperature, for instance, but believes that is at least another two to five years down the track.