By Glen Dimaandal

Nanotechnology: Infrared Sensors

Sensors are bigger (and smaller) than ever. The popularity of sensors has grown exponentially with the increasing demand for smart-products, and can be found in most electronic devices, cars, phones etc. With the mass production of sensors, comes the budget and ability to develop them further, allowing for a much wider variety of applications.

Most recently, the Defense Advanced Research Projects Agency (DARPA) and researchers at Northeastern University (in Boston, America) announced that they have developed an infrared sensor that runs on essentially zero power. This incredible feat of nanotechnology innovation has the potential for much grander impact than anything that has been seen before.

What Are Infrared Sensors?

Infrared sensors are electrical devices used to collect and record data from the surrounding area. They do this by either emitting or detecting infrared radiation, which can be used to detect movement, proximity, space and heat.

The evolution of the smartphone, and its use of various sensors, has opened up the market for sensors – making it a very lucrative business to get involved with.

The wide range of uses and demand has meant that the IR sensor has become readily available and affordable. RS Components highlights the different infrared sensors available online. Whilst these kinds of sensors are perfect for everyday electrical uses, researchers have started to look at ways to have a bigger impact.

With mass production driving down the cost of infrared sensors, tests and experiments are cheaper to carry out, which has speed up the rate of development over the past few years.

Zero-Power Sensors:

Researchers from Northeastern University have developed a zero-power infrared sensor for the Defense Advances Research Projects Agency. Beforehand, a dormant infrared sensor would have to be connected to a power supply in order to detect any IR wavelengths. Now, the smart sensor will be able to identify infrared wavelengths whilst in a ‘sleep mode’ by harnessing power from the same wavelength it is designed to detect.

DARPA wanted to employ a large network of sensors in remote locations. But, with sensors that require maintenance and constant power supplies, the task was too costly and the results, unreliable. Northeastern have found the solution in creating a sensor that requires no power supply, and in turn little maintenance.

Northeastern reports, ‘When the sensor recognizes a specific infrared wavelength signature, it uses the tiny amount of power contained in the infrared radiation to wake itself up.’

The sensors have small mechanical switches that can be triggered by wavelengths of light. Once triggered, the sensor harnesses the energy from the wavelengths to close a pair of electrical contacts, which in turn creates an electrical connection between a battery and a load. Northeastern’s design of the sensor’s nanostructures, allows the device to absorb most of the energy in a wavelength, and reflect other wavelengths simultaneously. Utilizing the energy from the wavelengths in this way means that the sensor can remain dormant for years, until needing to detect an object.

Sensors in Warfare

DARPA have claimed that this innovation could be used across a whole new range of applications including ‘detecting human bodies or fuel-burning cars, identifying wildfires before they become uncontrollable, or pairing with laser sources for new types of remote control and communication applications.’

This will make warzones and other high-risk situations much safer. Often, in these types of environments changing the battery of a sensor is an unnecessary worry, so these new smart sensors will not pull focus from the task at hand.

Future of Smart Sensors

As well as warfare, DARPA have big plans for how else these nano-sensors could revolutionise the world.

The design of the sensor can be altered to recognize various other signals. DARPA suggest that be changing the design, infrared sensors could be used to detect chemicals, specific wireless radio frequency or magnetic fields. If these sensors were then implemented across cities, the data collected could highlight what changes needed to create a city better for the environment.

Matteo Rinaldi, associate professor of electrical and computer engineering at Northeastern, explains his vision: “If we have all these sensors embedded in the infrastructure of the city, that would increase awareness making everyday life safer and more efficient.”

If Rinaldi’s vision comes to fruition, the more accurate and more real-time results of the information gathered from these sensors could start to detect things such as environmental stressors, security threats, traffic, pollution and so much more.

It’s exciting to see the smallest of nano-technologies starting to have a big impact on the way we live our lives.