How new sensor technology opens up smarter presence detection & temperature measurement
03 March 2020
Novel sensor technology can bring about new and more efficient presence detection in, for example, the construction, facilities and real estate sectors, as well as in consumer electronics devices.
This article was originally featured in special supplement on Designing for energy efficiency, brought to you by EPDT & RS Components [read the digital issue].
In buildings, the solution is a small, inexpensive, battery-powered and IoT-caged sensor that will also be able to be connected very quickly with the help of the upcoming 5G networks; meanwhile, battery-saving solutions for consumer electronics devices can be integrated into solitaire sensor elements mounted into the bezel or cover of products. Anders Jansson, CTO at Swedish nanotechnology IR sensor company, JonDeTech explains how...
A rapid technological development within what is known as the Internet of Things (IoT) means that more and more things in our everyday life will be connected. The connection is made with the help of a gateway or a hub, which can collect data from a large number of sensors, which it then sends to the cloud via, for example, 5G. IoT and sensors will be each other’s preconditions in a variety of technical solution areas in this connected world. One such area is smart homes and buildings. Here, the development is very fast – from older sensors that control a relay that turns on and off a lightning system – to a whole new generation of sensors that can send data to just one gateway, which in turn controls the lamp exactly the way you want.
Another strong trend within the consumer electronics industry is to use presence detection to optimise battery life in battery-powered devices, such as laptops or tablets. With a sleek and passive presence detector, manufacturers are able to optimise their products to only use battery-powered systems when someone is using the device, in other words, when they appear in front of the device. This not only improves battery time, but also prolongs battery life, due to decreased need of charging.
Today’s pyro electric sensors provide limited presence detection
Most of today’s sensors for presence detection are built with pyro electric sensors. But its properties are limited and can only sense changes in temperature, making them less suitable for areas where the user is expected to remain, for example in a room or in front of a computer. The new sensor, on the other hand, has the ability to detect human presence by detecting the heat radiation. In this way, it is much better at detecting immobile people in a room, office space or in front of a unit, like a computer or a tablet.
Improved thermopile sensor an important component for smarter presence detection
So how is this sensor constructed? The new generation of presence detection is equipped with a so-called thermopile, which is manufactured using nanotechnology. Thermopile is a series of connected thermocouples – a thermocouple is a pair of two materials with different Seebeck coefficients – that can convert thermal energy (heat energy) into electrical energy. They can be used to measure absolute or relative temperature and heat flow. This can in turn be used to detect, for example, movement or presence. Moreover, they are passive and do not consume any energy when not measuring.
New applications with potential to save energy & increase safety
Common areas of use include smoke and gas detection, movement, absolute temperature measurements, heat measurement and control of heat-sensitive parts and plumbing. Other areas of use include smart offices or public spaces such as libraries, for example, to see if a place is vacant or not. By using the sensor to wake a device only when someone is present, you can reduce the energy consumption and extend the battery life. The new type of sensors can potentially also be used to activate biometric authentication systems, such as fingerprint scanning or facial and iris recognition, which consume a lot of energy when active.
The sensor’s ability to measure temperature on a surface without being in contact with the object enables fast and accurate measurements in products like ear thermometers, small handheld devices such mobile phones and temperature surveillance inside buildings and offices. They can also be used without encapsulation inside products to measure and monitor temperature on, for example, product casings/housings, batteries or other heat sensitive electronics. An extension of the laptop application, the sensors can detect ‘life’ inside of a closed car, parked in the sun, before the heat rises to deadly temperatures.
Today, we often measure air temperature; however, the air is heated by the objects in it. By measuring the ‘comfort temperature’ – taking heat radiation from walls, desks and other objects, into consideration when we measure the temperature – we can better predict whether the temperature in an area will rise or decrease, before it does. This application can be used in IoT and automotive applications, as well as in mobile phones.
Nanotechnology makes the sensor extremely thin, flexible & cost-effective
The sensor itself is based on nanotechnology, which results in a lot of advantages. It measures only 0.17 millimetres in thickness and is almost entirely made of plastic. The plastic piece is very robust and can be used without the metal housing, or protective cover, which is often used on conventional sensors. This makes integration into existing products and solutions more flexible and easier.
In addition to being thin and robust, the sensor is also very flexible, but also cost-effective to produce in large volumes. It makes it suitable for all types of applications that require small sensors where temperature or heat flow should be measured, for example, in different types of presence detection.
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