Feb 25, 2024

11 min read

What are self-powered sensors and why are they transforming IoT?

The Internet of Things was touted to be the biggest thing to happen to tech since, well, the internet. Has it lived up to the hype in real life? The answer has to be yes - The internet of things has radically changed the way we go about our lives. The internet is no longer just about e-mails, web browsing and buying flight tickets - far from it. Today, the internet can’t be left out of practically any kind of activity that goes on in the world.

This transition that the internet has undergone - from being a pretty nifty tool for information exchange and communication to something that’s indispensable in running our everyday lives is something many of us have lived through and witnessed first hand.

Today, the internet, as we know it, is undergoing yet another transformation - It is moving beyond the confines of traditional computing devices such as computers and mobile phones and penetrating into the wider array of everyday objects around us - this, essentially, is the internet of things at work. 

But be that as it may, it is a unanimously accepted fact that while the Internet of things has blown up tremendously in the last few years, it is yet to reach the dizzying heights that it was predicted to reach. 

Why is this?

Like anything else, there are a number of reasons as to why IoT failed to live up to the initial hype that it generated. But more than anything else, the principal reason for this lackadaisical showing was the battery problem. 

If the internet had to become truly limitless, then it was not going to be powered by batteries - that much was clear. 

But, if not batteries, what then?

Wireless sensing become self-powered

In retrospect, it sounds pretty simple, doesn’t it? If batteries are the problem, then why not get rid of them altogether?

Well, yes, but you have to remember that for decades, we actually looked at batteries as the holy grail of all things wireless. For wireless sensing to have started looking past the battery - in a major way no less - took quite some doing. 

But here’s the thing

We HAVE well and truly entered an era where IoT designs are no longer tethered to batteries - we have entered the era of the self-powered sensor. 

And we promise we are not being hyperbolic when we say that self-powered sensing is the biggest thing to happen to the internet of things and maybe even the future of technology, to be fair. 

And that’s not all - self-powered sensors don’t just enable a more robust and pliable IoT, but they actually allow IoT to go where it’s never been before - or actually, could go before!

In the sections below, we’ll take a closer look at what self-powered sensors are, how they work and why they matter. 

What is self-powered sensing?

Sensor networks form the building blocks of any IoT setup. Be it smart cities, smart factories or even automated surveillance systems in apartment buildings, they consist of sensor networks that work together to collect, relay and process data, in order to perform certain predefined tasks and optimise them. 

It should come as no surprise to anybody that wireless sensors need to have a power unit that supplies energy to them. 

This is where the trouble begins for battery-based solutions - imagine a sensor network consisting of say 100 sensors - In any real use-case, these sensors will most likely be placed in various locations across a facility. Moreover, a lot of these locations are also likely to be hard-to-reach spots. It makes sense to use sensors in the first place, only because they can be positioned in pretty remote places and collect data.

Now, considering these variables of high mobility, wide geographical distribution and wireless operation, sustainable operation of wireless sensors using batteries becomes a major question mark. In fact, it becomes a near impossibility if you factor in sustainability and economy. 

Voila! Enter self-powered sensors 

Cutting right down to the chase, self-powered sensors, as the name suggests, are sensors that are able to generate the energy that they need to function by themselves - i.e they do not need to be powered by an external source of power such as batteries. 

It is really that simple. 

“Ok, so the next question becomes,if they don’t need batteries, where do these self-powered sensors get their juice from?”

Great question! Well, they just suck it out of thin air really! 

More on that later, But for now, let’s take a brief look at the interesting and eventful history of self-powered sensors.

The idea for self-powered sensors that harvest energy from their surroundings (i.e ambient energy) and use it to transmit signals was first proposed by a scientist called Wang all the way back in 2006! He was the first to propose the radical idea of cutting the sensor off from batteries altogether and making them autonomously powered units that could communicate with a larger network. 

Since then, advances in energy harvesting technologies have enabled self-powered sensors to go from strength to strength in the IoT world, with newer and newer modalities emerging every day.  

Sensors have come quite a long way since their inception. Speaking strictly technically, the earliest sensors that fit any accepted definition of what a sensor is, were devices called sundials that were invented in Ancient China around 700 BC. In 400 BC, this led to the development of a device called a “sinan” which was instrumental in the furthering of maritime activities back then. Cut to the 21st century and sensing today is about MEMS - or in other words, nano-sized particles which can collect and transmit data. The advent of self-powered sensors based on energy harvesting technology is probably the biggest enabler of this drastic improvement in our sensing capabilities. 

After all, it doesn’t take a very smart person to figure out that you can’t fit batteries into dust-sized sensor particles. 

Today, self-powered sensors are being used in all sorts of cool, futuristic applications such as smart cities, GPS systems, driverless cars, VR systems, entertainment devices etc. As we move further on this journey, they are only going to be playing a bigger and bigger role in shaping the world around us. 

“Ok, all that sounds good but what’s the big deal with these self-powered sensors? Like, what makes them so great? How do they make things easier?”

We need to take a look at where IoT is headed to understand that. 

Forests, Mountains and Oceans

As IoT started venturing out into uncharted terrain, it became more and more clear that the battery would be a cross it just couldn’t bear. With advancements in IoT, smart cities and smart manufacturing, sensors as a fundamental unit of signal processing started becoming a ubiquitous necessity. 

This trend is only going to continue at a blistering pace as we head into the future. 

Sensors are being placed in all sorts of locations and many of them are super-remote and inaccessible - as we mentioned earlier in the post, in a lot of cases, that is kind of the point of using sensors in the first place. These locations could include long-distance transmission lines, oil and gas pipelines, international optical cables, jungles, seas, hilltops etc. just to name a few. 

And that’s just one kind of remote.

With health technology booming like never before under the wing of IoT, sensors are increasingly being deployed in the inner recesses of the human body. 

So, with sensors being deployed in large quantities and that too in very hard-to-access spots, it is massive if they can power themselves. 

We’ve spoken about it in many of our posts before - maintaining and replacing the batteries in an operation comprising thousands or say even hundreds of node devices is a logistical nightmare. Actually, in a lot of cases, it’s more like a logistical impossibility. Also, that kind of a solution wouldn’t make any kind of economic sense. 

Think about it - you’ve got sensors placed inside bridges, inside tunnels, under high-speed rail lines etc - now, how in the world would it make sense for these sensors to be powered by batteries, which even in the best of scenarios, need to be replaced at some point?

And trust us when we say this is by no means a comprehensive and exhaustive list of all the inaccessible places that IoT sensors can find themselves in - forests, mountain-tops, in the oceans - these are not far-fetched imaginary use-cases - we are truly witnessing an era of hyper-connectedness where sensors play an important role in nearly all aspects of human life. 

Advantages of self-powered sensors

1. Lower cost for businesses

Batteries cost money. Scheduling regular maintenance costs money. Arranging for used batteries to be disposed of safely costs money. With self-powered sensors, all of these costs are practically eliminated in one fell swoop.

From a business perspective, this is huge. After all, any business is only going to adopt a new technology only if it’s going to translate into savings. With battery-based IoT solutions, businesses were, understandably, quite hesitant to cough up the initial investment required to set up these systems. However, with energy harvesting based designs, it is very likely that they would be more bullish and optimistic. 

Self-powered sensors make for a lower initial investment, a lower bill of materials (up to 90% reduction in some cases) and a significantly reduced maintenance cost over the period of ownership. Now, if you are a business owner, what’s not to like?

2. Better for the environment

It should come as no surprise to anyone that nearly every move we make as an industrialised civilisation comes at a cost to the planet. Thankfully, more and more people have started to wake up and take notice of the rate of ecological damage that is underway. 

Batteries, ironically, were touted as the “environmentally friendly” energy option just a few years ago. And for the most part, this is understandable - compared to fossil fuels, they are a more sustainable way of obtaining power. 

But as we’ve explained in detail before, batteries do come with a pretty ecological and humanitarian bill themselves. The more we find out about the atrocious difficulties posed to entire communities in order to mine lithium and cobalt, not to mention the ghastly impact it has on local water supply and biodiversity, the harder it gets to just turn a blind eye. 

And it’s not just the mining for these minerals that makes batteries ecologically questionable - it’s also the disposal. Batteries need to be discarded very carefully, which in a lot of cases, they are not. Even if, hypothetically, all of the required precautions are taken all of the time, we simply can’t be throwing away hundreds of billions of batteries. It’s simply not an option. 

In all fairness, this has got to be the biggest point in favour of self-powered sensors. 

3. Leaner, meaner and more flexible

Self-powered sensors are smaller and lighter than their battery-based counterparts. The decreased heft and bulk translates to more freedom if you are tasked with designing the device around the sensor. 

Imagine you are meant to design a piece of smart clothing - say, a smart sneaker, that tracks the number of miles you’ve run and helps you out with tips to improve your running - now, isn’t it obvious that a smaller chip with fewer moving parts would give you more freedom on how the shoe that surrounds it can turn out?

This is a massive advantage, especially from the point of view of manufacturers. 

4. Self-powered sensors can literally go anywhere

The whole point of IoT is to unhook the internet from desks and handheld devices and literally take it everywhere. An IoT that is bound by limits on location and terrain isn’t much fun. 

With self-powered sensors, IoT is well and truly unshackled. Freed. Unchained. 

Self-powered sensors can literally be deployed anywhere. Let that sink in - ANYWHERE!

Because they are theoretically meant to require ZERO maintenance, they can essentially be chucked deep into the ocean or even sent to outer space, if you like. More realistically, think about bionic implants or nano-sized diagnostic devices that are designed to be deployed inside the human body - well, with self-powered sensors, they are eminently possible. 

This is another major advantage that self-powered sensors bring to the table - they truly enable the internet of things to break its chains and scream towards the seemingly endless possibilities that it was always meant to empower. 

In a nutshell

At ONiO, we have zero doubts about the fact that the future of IoT rests on energy harvesting based sensors. Self-powered sensors are simply the only way we can bring our crazy IoT visions into reality.

With the human population growing at an unheard-of rate, radical solutions are the only way we are going to cope with our mounting energy needs and the impending energy crisis. Solutions like self-powered sensors emerged out of a genuine need - a stifling, cramping necessity - to innovate. It simply remained our only option. 

If that sounds grim, it shouldn’t. Because, the very fact that we are able to produce self-powered sensors that can draw energy from the air around them sounds pretty inspiring. It’s a testament to just what’s capable when people put their minds to it. 

About the author

Abishek Swaminathen

Senior Content Manager

Abishek is ONiO’s senior content manager. A medical doctor by profession, he stumbled onto a writing career almost by accident, as it were. Words have enthralled Abishek since the day he first held a book and at ONiO, he channels his inner wordsmith towards providing our subscribers with regular doses of fun and informative content.

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