Sensing The Future - The History and Evolution of IoT Sensors

Sensors are all around us, in today’s connected world. Acting as conduits that connect the physical and digital worlds, IoT sensors have come a long way since their inception. With the number of connected devices in the world only set to go up in the coming years, IoT sensors are only going to increase in relevance - In 2020, it was estimated that there were 15.1 billion connected IoT devices in active use worldwide. This number has been growing at a staggering rate - by the year 2030, it is expected that there will be well over 29 billion active IoT devices!

Now, take a moment to wrap your mind around that number. That’s about 4 IoT devices for each person on planet earth! IoT devices are equipped with an entire range of sensors - to cater to various functionalities. What this means is that, as we speak, there are over a trillion IoT sensors buzzing away around us in the world right now! A Trillion!

What are these sensors doing?

They’re collecting data - plain and simple. Various kinds of IoT sensors, are specialised to collect different types of data from their surrounding environment. This data is absolutely reshaping the world around us and the way we interact with it - farmers are relying on pH sensors, moisture sensors, NPK sensors etc to optimise their fertiliser and water input to achieve high yields and prevent pests and plant diseases; Smart factories are using sensors to monitor the health of their machinery and avoid unexpected losses, boosting their margins and overall productivity; Motion sensors, level detection sensors, light sensors, sound sensors etc are being used as parts of comprehensive sensor suites to transform our urban spaces into smart cities. 

It’s not just industry and public conveniences either - like we saw in the beginning of this article, smart appliances, as part of a broader smart home, employ various kinds of IoT sensors to automate various household tasks and customise them to user preferences - refrigerators that order groceries for you on amazon when your stocks run low; pressure sensors that warn you well before your taps start leaking; air quality sensors that work with your air conditioning unit to make sure the air in your room is just right - the level of convenience, seamlessness and comfort enabled by wireless sensors is simply absurd!

Sensors Evolution - A Timeline Through The Decades

The modern day wireless sensor is a result of decades of iterative development, driven by increasing demands of a tech world that was growing and evolving at breakneck speed. In the late 20th century, sensors were very rudimentary devices that could detect basic parameters such as light or temperature - they were usually deployed in industrial plants or in early versions of computers. 

As our information processing capabilities started growing, the scope of these sensors exploded in a massive way, leading to the advent of highly sophisticated sensors that could detect a wide range of environmental parameters like motion, humidity, pressure etc. This was primarily driven by the market’s exploding demand for intelligent and efficient sensing systems that could adapt to changing conditions in real-time, performing a role of optimisation in various kinds of industrial and consumer-facing settings. 

Let’s take a brief look at the history of the modern wireless sensor:

Sensors may sound like they don’t belong in history - they seem a pretty recent invention. However, if we define a sensor as a device that scans its surroundings, sensing changes in a particular variable or parameter, then we’d have to go way back to the 17th century, to rudimentary thermometers, which were essentially primitive temperature sensors. The 1800s saw some advancements in devices that could detect changes in pressure and light levels - i.e early pressure sensors and light sensors. 

The concept of connecting everyday devices to one another and to the internet, in order to drive higher levels of functionality and intelligence can be traced back to the 1990s. Kevin Ashton coined the term “Internet of Things” all the way back in 1999. Since then, wireless sensors have made rapid strides - becoming smaller, less power-hungry and more sophisticated. 

With the turn of the 20th century, sensor innovation started taking off like never before, driven by a massive technological boom - The modern day IoT sensor owes its existence to some key 20th century developments. 

Transistors (1947) - It is a well known fact that wars accelerate the evolution of technology. In the period immediately after the second world war, the transistor absolutely revolutionised the world of electronics - making it possible for them to be shipped with compact and affordable components. Before transistors, electronics used vacuum tubes - which were heavy and bulky. Moreover, they were also extremely power hungry. Transistors were substantially smaller in size compared to vacuum tubes and did not require nearly as much power. Transistors allowed highly complex circuits to be integrated onto a single chip.  This was a notable milestone in the history of the modern day sensor.

Microcontrollers (1970s) - Microcontrollers were developed in the 1970s and represented a massive leap forward in sensing technology. Microcontrollers are essentially tiny computers that are entirely based on a chip. Microcontrollers allowed the data from multiple sensors to be integrated within a single device. Moreover, microcontrollers that were built into sensors enabled on-board data processing, completely bypassing the need for a separate backend operation or at any rate, reducing its load. This reduced the total data-load that had to be transmitted, which in turn, reduced bandwidth requirements and enabled some applications to start featuring real-time decision making. Microcontrollers, perhaps most importantly, enabled sensor programmability - this meant that sensor functionality could be customised to match the requirements of specific use-cases. This was a huge boost to the versatility of functionality of sensors.

RFID (1980s) - Radio-frequency identification or RFID technology, brought a whole new dimension of capabilities to wireless sensing. RFID, for the first time, allowed objects to be identified and tracked without them being directly in the line of sight.

Wi-Fi (1997) - The advent of Wi-Fi in the 1990s meant that high-speed wireless internet became a real possibility for the first time. This meant that sensors could now transmit large amounts of data seamlessly.Wi-Fi enabled sensors to be integrated into networks much more easily, playing a significant role in the colossal development of IoT technology today.

Bluetooth (1998) - This was another big landmark in the development of modern day sensors as well. Bluetooth technology allowed sensors the massive luxury of reliable short-distance wireless communication. This meant that sensors located in close proximity could “speak-to” one another without the hassle and expense of using Wi-fi.

Then, there were a couple of key developments following the turn of the century that led to the powerful, diminutive and highly versatile IoT sensors that we know today. 

MEMS (Microelectromechanical Systems) - The development of MEMS in the early 2000s remains a very significant step in the evolution of modern day IoT sensors. MEMS allowed IoT sensors to be rendered in miniature form, making it possible for sensors to be deployed in the numerous applications that we see them in today. Use-cases like smartphones and fitness trackers are possible for sensors today simply because of MEMS. They made sensors versatile, compact and inexpensive.

LPWAN Technologies - The advent of LoRaWAN and NB-IoT in the 2010s has been huge for the emergence of modern standards in sensor technology. They allow sensors to be deployed in far-flung, remote corners of the world where internet and power access are questionable, at best. LPWAN technologies enabled the expansion of IoT into the big, wide world - opening up an unimaginably diverse range of use-cases in the process.

Demand Driven Innovation

In the early years, IoT technology was based on connecting everyday objects to computer systems or large computer networks - this is how these early smart objects were controlled and monitored. 

This was revolutionary at the time, with sensors being used to blur the lines between the physical and digital worlds. However, there were some pretty hefty limitations as well - these sensors were taken straight out of industrial settings and were often quite bulky and expensive. They were also massively power hungry, demanding wired connections or frequent battery changes. This made it impossible for them to be deployed in remote use-cases. There was a growing need for more energy-efficient sensors. 

Moreover, sensors in the past were largely restricted to single data types - i.e a given sensor was limited to being able to gather only one type of data - like temperature, pressure etc. This meant that early IoT solutions were straitjacketed and could not really spread their wings in terms of ingenuity or scale - this limited the range of problems that they could be used to solve. 

Processing power was also an issue with early sensors - they lacked the sheer muscle that was needed to process the data they collected; this meant that early IoT devices had to rely on the cloud for processing and analysis, adding to latency and overhead in the process. 

The market was clamouring for a new breed of IoT sensors that could solve these issues. With IoT technology being adopted across various sectors at an increasingly rapid pace, there was a tremendous incentive for innovation in the sensor space. The market exerted a number of pressures that fueled the development of next-gen sensor technologies -  these were:

Cost Effectiveness - The scale at which IoT technology was growing was so massive that there was a huge demand for ultra-low-cost sensors that could be deployed in large numbers without much thought.

Size - Sensors needed to drop some serious heft and become diminutive in order for them to be seamlessly integrated into various wearables, implants and smart devices.

Low-Power - Battery replacements were a serious limiting factor in the early years of IoT. The battery problem severely curtailed the growth of IoT technology for a long time. In addition to the repeating costs, there was the huge environmental impact of batteries to consider. There was a growing demand for energy efficient sensors.

Smart and Autonomous - With use-cases becoming more diverse and expansive, there was a huge need for sensors that were capable of doing a fair share of the information processing and filtering themselves - relying as little as possible on mainstream computing devices. This would save a ton on data transfer and make systems more latency free and responsive, enabling real-time solutions.

Multimodality - IoT solutions kept getting more complex and as a result, they demanded wireless sensors that were able to measure multiple parameters at the same time - offering a more rich and variegated picture of their environments. 

Newer, Faster and Better Sensors

These pressures led to the development of modern day IoT sensors. 

Today’s wireless sensors are small and versatile - sometimes even as small as a grain of sand. This enables them to be deployed in a variety of use-cases across a wide range of form factors and environments. 

Secondly,modern day sensors tend to be quite miserly with their power consumption, often being able to operate for months or years on end with no battery replacements. Better yet, we have seen the advent of energy harvesting powered sensors that don’t need any external power source whatsoever (we’ll see more about them in the following section). 

Thirdly, wireless sensors are getting smarter and more multi-talented - allowing for multiple parameters to be monitored at the same time using a single device. They are also starting to feature some pretty serious on-board processing power, which enables local decision making. 

Fourthly, mass production and innovation have led to sensor prices falling precipitously in the last decade or so. This means that they are now way more affordable in large numbers, allowing for ambitious and powerful IoT solutions that can take massive problems head on. 

Perhaps most importantly, today’s IoT sensors are versatile and flexible - boasting of incredible levels of adaptability and interoperability. Open standards and flexible software interfaces mean that the powerful sensors of today are able to be seamlessly integrated into various kinds of IoT systems, across a stunning range of industries and applications. In fact, it might be fair to say that there isn’t a single major industry on the planet which hasn’t been transformed by IoT technology in the past few years.

Batteryless Magic - Self-Powered Sensors

Thanks to advances in energy harvesting technologies, today we are able to produce sensors that are 100% self-powered and battery-free. 

Sounds pretty crazy doesn’t it?

It’s true though. Batteryless IoT is very much a reality today. These sensors are able to draw power from their surroundings - be it in the form of radio waves, vibrational energy, heat, light or a number of other sources. 

They are able to harness the energy required for their operation from the surroundings and completely eliminate the need for any external power source. This gives them a number of pretty compelling advantages over their battery powered predecessors. 

Firstly, there is the money saved on battery replacements and periodic maintenance. Self-powered sensors are way cheaper to run over their lifetimes than battery-powered sensors. That number gets huge especially when large scale deployments are considered.

Secondly, there’s the environmental benefit of preventing hundreds of millions (if not billions) of batteries from ending up in landfills and oceans. This one’s a no brainer. 

Thirdly, self-powered sensors offer an incredible amount of flexibility in terms of where they can be deployed. The sky is truly the limit with batteryless sensors - they are totally untethered and can be taken wherever the imagination goes. They can be deployed in bio-implants, machinery, hilltops etc, with no second thought. 

Energy efficient sensors are one thing - but when sensors are self-powered and energy efficient, they can really bring an unbelievable amount of value to the table. 

Incredible Possibilities

The future of IoT sensors is going to be filled with exciting new developments - firstly, they will continue to become smaller, smarter and more invisibly integrated into the fabric of our everyday lives. They will start to wedge themselves in practically every part of our surrounding environments and feed endless streams of pertinent data to the devices around us, making them more intuitive and snag-free. 

Moreover, the emergence of batteryless sensor technology is incredibly promising from a sustainability point of view, especially amidst this climate of rising ecological uncertainty and climate related distress. 

The story of wireless sensors is far from finished though. As we move into the future, we are going to see new materials, sensing mechanisms and data analysis modalities. There is a good chance we’ll get to see some pretty futuristic stuff like self-healing sensors and completely embedded sensors. 

The sensors of tomorrow, as they grow in sophistication and power, will transform entire industries and unlock a data-driven future where we could get to see incredible levels of efficiency, sustainability, productivity and human well-being. 

Now, that’s something to look forward to!