A fundamental function of IoT devices is sensing and processing of physical parameters. The sensor acts as a transducer that converts a physical quantity (such as temperature, CO2 concentration, blood glucose level, etc.) into an electrical signal that can be processed, stored and communicated. If the IoT extends to billions of sensors around the globe, this will generate an unprecedented amount of data. Storage and interpretation of this Data Everest represents a major challenge for a successful implementation. Cloud storage already laid out the foundations to a data infrastructure, but the solution will require more than just increasing storage capabilities.
It is equally important to find intelligent solutions to reduce the data load. Classic sensors are ‘stupid’ in a sense that they can either record data or not, the amount of data generated is either zero or plenty. In the field of ultra-low power electronics, sensors are paired with smart circuits that control the sample rate (i.e. the number of times a sensor signal is recorded in a certain time frame) depending on the situation. Yet, this type of data reduction might not be sufficient for IoT. Future ‘smart’ sensors might have neuronal intelligence that monitors and filters the data directly on the node. The sensor will decide if the recorded data is relevant and needs to be stored or transmitted. As a result, only a small fraction of the acquired data is moving into the cloud.
Next to data storage and handling, there is plenty of open legal questions on data ownership, data distribution and on the protection of end users. Who is going to own the data that is recorded? The sensor producer, the cloud storage host, the software provider or the individual? The content embedded in the data can be extremely valuable, even once anonymized. Can it be sold to other companies and who earns the profit? How is the individual or a company protected from data theft if the data is not stored on the user’s device? What is the government’s role in this? To sort out these and many more related questions, governmental bodies and the IoT community are in demand to work out a consistent set of laws that can be applied on a global scale.
Although the cost of individual sensors is reducing with increased automation and quantities, complete devices that sense, process and communicate are typically in the double figures. For the widespread distribution IoT envisions, device cost will have to be reduced drastically. The actual price will depend on the application but should not exceed one to several dollars per unit. This implies that the devices are mass produced in automated production lines.
This is the already the case for sensor and electronic components, however not yet possible for the assembly and packaging components. Modularity and standardization will aide to the goal of a single dollar IoT device. Cost will not only originate from device manufacturing itself but also from energy and material supply as well as from environmental oncost. This demands for an extended recycling infrastructure and culture. Finally, the biggest share of the cost and the profit will not be found in the hardware but in the domain know-how and data evaluation.
Recent developments in ultra-low power electronics, sensors and communication protocols drastically reduced the energy demand of IoT devices. Even so, every single node will require some form of energy supply at the end of the day. In many applications, electric wiring or a battery-based energy storage might be sufficient, but there will always be use cases that demand for portability combined with extended or unlimited device runtime. This is particularly relevant in applications in remote areas or in the wearables sector. The combination of portability and unlimited runtime could be achieved using complementary energy harvesting solutions.
Energy can be harvested from the environment in form of light, movement, temperature differences, induction and chemical reactions. The different options with their individual advantages and drawbacks will be evaluated in a following article. Energy harvesters typically feature transient power profiles that require power conditioning and buffering to operate the connected electronics. Just like all other components of an IoT system they need to be small and cost-efficient.
When IoT devices are used in direct contact with the human body, the previously discussed requirements need to be extended by wearabilty aspects. Devices need to interface with the body in a comfortable and safe way without compromising the functionality. In terms of safety, this can be achieved by use of non-toxic and non-allergenic materials, encapsulation of potential safety hazards and prevention of hard or sharp edges.
Comfort is a subjective feeling that is hard to access or measure, but generally, the use of flexible and skin conformal materials, small dimensions and light weight promote a positive user experience. To ensure user acceptance, ideal wearable IoT devices would be imperceptible to the wearer and integrate seamlessly with the body or clothing. Fulfilling this goal often contradicts the most efficient solution from a hardware standpoint and compromises between performance and wearability need to be found.
The IoT is still facing a lot of challenges in data handling, cost, energy supply and wearability but solutions are already in the pipeline. In the next article, different options to supply IoT devices with energy will be discussed.