The role of WiFi sensors in the IoT

Bruce Leith

Blog by: Bruce Leith - 29 / Mar / 2019

What is the Internet of Things (IoT) made of?

One way of visualising IoT ecosystems is to think of them as composed of three layers. First up, we have a physical layer, comprising the sensors or devices spread out throughout a particular environment. The point of these devices is to collect (and sometimes harness) the data which the IoT aims to collect. The location of a vehicle, the temperature of a room, the weight of a load – any and all of this information is collected up by said devices, before being aggregated and digitised for further processing and analysis.

This brings us to the second layer – the network layer. Wireless connectivity links up that multitude of devices to some kind of analytics platform or engine, which can then process it to turn it into tangible business insights. The analytics platform or engine forms the third layer – the application layer.

Let’s turn our attention specifically to the network layer. Which technology is best for providing that connectivity? Bluetooth, Z-Wave, Zigbee and LoRaWAN are all wireless communication technologies which have been harnessed for IoT ecosystems. But the most popular of all – and the one most familiar to consumers – is WiFi, with cumulative global shipments of WiFi-enabled devices surpassing 10 billion in early 2015, and forecast to expand rapidly from there. Not all of these shipments are for IoT use cases, but those specific shipments are still expected to hit around 500 million annually by 2021.

Why, then, is WiFi such a popular technology for embedding in IoT devices?

One key factor is cost. As broadband internet availability becomes ever more widespread, so the cost of connecting to it becomes lower. As such, more and more devices and sensors are able to have WiFi connectivity built into them as a matter of course. WiFi also offers much greater range compared to many competing connectivity technologies.

Then there is the question of ease of setup and management. Particularly in consumer contexts such as healthcare wearables and smart home devices, WiFi networks are familiar and established.

However, WiFi sensors for IoT ecosystems are not without their challenges. WiFi has traditionally been a more power-hungry technology compared to other forms of connectivity, so to remain practical for IoT use cases it needs to be designed to be as power-efficient as possible. WiFi-enables sensors deployed throughout a typical IoT ecosystem might be plugged directly into a power source, rechargeable or battery-powered, with the latter category having the highest power sensitivity. This can make WiFi a more challenging option for them, but there are workarounds. Power-centric sensor designs can mean that even battery-powered devices are suitable for WiFi-based IoT networks, if those considerations are built in from the ground up.

As the IoT continues to expand and the bandwidth demands placed on IoT ecosystems grow, the designers and manufacturers of WiFi-enabled sensors will need to prioritise the power question.

Want to know more about the potential of the internet of things? Get in touch with Tern.




Topics: IoT, IIoT, sensors, wifi

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