Asian Games "black technology", what is passive Internet of Things?
With the rapid development and wide application of Internet of Things technology, we can feel the power of Internet of Things technology in all aspects of daily life.
Smart courier locker without texting or calling to specifically notify; shared bikes can be found everywhere on both sides of the road; Wearable devices such as smart watches and smart bracelets that can collect data such as heart rate, step count, and sleep quality; Smart appliances such as smart TVs, smart speakers, etc. that are controlled by mobile phones or sound... These are all practical applications of IoT technology.
In addition to daily life, IoT technology plays an irreplaceable role in various fields such as smart cities, smart transportation, smart agriculture, and smart healthcare.
The recent Asian Games used a "black technology" - passive Internet of Things. What is the difference between passive IoT and IoT in general? What are its advantages?
Smart home (Image source: Ver Gallery)
Step into the world of the Internet of Things
The biggest difference between passive IoT and general IoT is the power supply.
Internet of Things technology has gradually realized the development and transformation from human-to-person communication, human-to-thing communication, and then to thing-to-thing communication, with a wide range of application prospects. However, most traditional IoT devices require built-in batteries or connections to power outlets to provide the required energy. This limits the deployment location and usage time of some IoT devices.
For example, if the battery of a device runs out, it needs to be recharged or replaced with a new battery. At the same time, the battery life is short, frequent replacement brings inconvenience to the user, and the use of the battery increases the cost and volume of the equipment, and improper disposal of the battery will also have a negative impact on the environment.
In addition, wired power devices may cause many problems in deployment due to the complexity and requirements of wiring, such as deploying IoT monitoring devices outdoors may require a lot of effort and cost to lay power lines. As a result, passive IoT technology came into being, and its goal is to solve the problem of traditional Internet of Things in terms of energy supply.
The "source" in passive IoT refers to the power supply, a technology in which devices do not rely on internal batteries or external power sources, but operate by capturing energy from the surrounding environment, such as light, heat, radio waves, etc., to achieve self-power.
This technology can both meet the demand for IoT devices to be without power for long periods of time and reduce the potential negative impact on the environment.
Passive IoT is mainly realized through energy harvesting, backscatter communication, and low-power computing technologies. Energy collection methods mainly include light energy, vibration energy, thermal energy, radio frequency and other energy collection, among which radio frequency energy has become the focus of passive Internet of Things research because it can solve the two functions of energy acquisition and signal transmission modulation at the same time.
IoT concept map (Image source: Ver Gallery)
In addition, backscatter technology is at the heart of passive IoT communication patterns, allowing devices to communicate by reflecting or forwarding signals received from wireless towers. The signal energy received by the device is used both to drive the operation of the device and to send it out in reverse as a carrier of information.
Imagine a mirror that reflects sunlight on the surface of the sea, both using sunlight to provide illumination and forming signals by reflecting sunlight. Similarly, passive IoT devices use both radio waves to power themselves and these waves to transmit information, which is how passive IoT works.
At present, the most representative traditional passive Internet of Things technology is RFID, that is, radio frequency identification technology, the second generation of ID cards, canteen meal cards, bus cards and other items are common passive RFID products in daily life.
Their main working principle is: the reader transmits a certain frequency of RF signals, when the tag is a passive node close to the reader into the effective working range, the RF signal sent by the reader will produce induced current to obtain energy, using this energy, the tag can send the information out, the reader receives it and transmits it to the background host for processing, the host controls the reader to complete the read and write operation, so as to realize the communication between the tag and the reader.
RFID tags (Image source: VER Gallery)
From the use of daily life, it is not difficult to see that the limitation of passive RFID technology is that the tag and reader must be close enough to the distance, that is, the communication distance is too short. In addition, the data read and written by the reader is relatively simple, and the reading and writing ability is weak.
Therefore, passive Internet of Things technology is committed to expanding new passive interconnection based on WiFi, Bluetooth, 3G, 4G and even 5G communication technology on the basis of RFID technology, which can use radio frequency signals widely present in the surrounding environment, such as cellular base stations, WiFi routers, TV towers, etc. as RF energy sources, and send RF signals to passive nodes so that passive nodes can obtain enough energy from them to complete the communication process with readers, thereby significantly expanding the communication distance.
What are the application prospects of passive IoT?
At present, passive RFID tags have been widely used in inventory management and anti-theft systems. They can help track and manage the inventory, sales, and more of your products, increasing operational efficiency. The use of passive RFID system item tracking can update inventory information in real time, improve inventory accuracy, and reduce the burden on staff.
In the transportation industry, passive RFID systems can be used for automated toll collection, vehicle identification, and cargo tracking. The unmanned toll collection system can realize the automatic identification and charging of vehicles with the help of radio frequency identification technology and improve traffic efficiency.
The metamorphosis of RFID from "recognition" to "perception" (Image source: Reference [1])
At the same time, passive IoT can also be used for the management of airline baggage, by scanning the RFID tag on the bag, it can realize real-time tracking of baggage and reduce the possibility of baggage loss.
The optimization of communication distance, equipment volume and equipment cost of new passive IoT technology can further expand the scope of IoT applications.
In the medical field, passive IoT is gradually playing a role in patient management and disease monitoring. For example, the use of passive sensors can non-invasively monitor the physiological condition of patients, such as heart rate, blood pressure, etc., and wirelessly transmit the data to the equipment of medical staff. This can not only reduce the human burden of traditional manual testing, improve data accuracy, but also provide the possibility for telemedicine.
In manufacturing, factories can prevent premature equipment failures by using passive IoT devices, such as temperature and pressure sensors, to monitor the operating status of factory equipment in real time. These devices can send fault alarms wirelessly, reducing the cost of regular maintenance and inspection.
In agricultural applications, passive IoT devices, such as environmental and soil sensors, can help farmers monitor the planting environment in an all-round way, automatically monitor soil moisture, light intensity, temperature and other indicators, and make corresponding agricultural decisions based on these data.
With the continuous development and optimization of passive IoT technology, its application potential in different industries will be increasing, which will bring more efficiency improvements and the emergence of new applications.
At the 2023 Hangzhou Asian Games, passive IoT also played a huge role. In the Asian Games Village charging station, with the help of a passive IoT tag, the charging station asset inventory system can automatically identify the experience vehicle, so as to grasp the experience vehicle's warehousing time, times and other information in real time.
Passive IoT technology in the Hangzhou Asian Games (Image source: Xinhua)
In the Hangzhou Asian Games e-sports competition venue, through passive IoT tags and sensors and other technologies, the temperature and humidity of the venue environment can be obtained in real time, so as to realize real-time monitoring of environmental temperature and humidity.
Passive IoT tags (Image source: Xinhua News Agency)
The wide application of passive IoT is inseparable from its significant advantages.
First, it reduces the energy consumption and maintenance costs of IoT devices, eliminating the need for regular battery replacement or frequent maintenance to keep the device sufficiently powered. Second, by eliminating the power supply, devices can be designed to be smaller and easier to install and deploy. In addition, passive IoT is more environmentally friendly because it avoids the generation and disposal of harmful substances such as batteries.
However, challenges also exist. Energy harvesting technology is difficult to provide large-scale, stable power supply, and passive IoT devices may not function properly in energy-scarce environments. In addition, passive IoT devices have limited computing and storage capabilities and may not be able to meet the needs of some complex tasks.
epilogue
The development of various modern technologies such as the Internet of Things and 5G is extremely fast, and the emergence of passive Internet of Things allows us to see the great prospect value it contains. It has been seen as the key to realizing the vision of "100 billion level interconnection", with the continuous advancement of energy harvesting and data processing technology, we will finally usher in the era of the Internet of Everything.
Bibliography:
[1] WANG Chuyu, XIE Lei, ZHAO Yanchao, et al. Review of passive perception mechanism based on RFID[J].Journal of Software,2022,33(01):297-323.DOI:10.13328/j.cnki.jos.006344.)
Produced by: Popular Science China
Author: Mu Ju (popular science creator)
Executive Producer: China Science Expo