UHF RFID Reader Design Based on Internet of Things
Guided Reading: “Internet of Things” can achieve global tracking and information sharing of items, significantly improve management and operational efficiency, reduce costs, and provide global supply chain links (warehousing logistics, manufacturing, item tracking, commercial retail, public services, etc.) Other industries bring deep changes. To achieve this vision, there must be a large number of distributed infrastructures – embedded RFID reader terminals with networking capabilities.
The concept of “Internet of Things” was first proposed in 1999. Specifically, it is an “Internet of Things” that covers everything in the world: In the Internet of Things, the ID code carried by RFID tags can be bundled with any item in the real world. Therefore, the object has a virtual “identity” on the network; through the ID code on the RFID tag, the attributes, features, and other information of the tag-attached item can be inquired and dynamically tracked on the network in real time. The “Internet of Things” can realize tracking and information sharing of products across the globe, greatly improving management and operational efficiency, reducing costs, and providing links to all aspects of the global supply chain (warehousing logistics, manufacturing, goods tracking, commercial retail, public services, etc.) ) Bring about deeper transformation. In order to realize the above vision, there must be a large number of distributed infrastructure—embedded RFID reader terminals with networking capabilities—to collect RFID tag information “anytime, anywhere” and achieve seamless and comprehensive coverage of the Internet of Things. Therefore, the goal of this project is to implement embedded RFID reader terminals with networking capabilities based on PIC32 technology.
System principle and technical characteristics:
The Radio Frequency Identity (RFID) system is mainly composed of three parts: an electronic tag, a reader, and a data management system, as shown in Fig. 1 [RFID system principle]:
The electronic tag part can be further subdivided into two parts, a tag antenna and a tag chip. Each e-tag contains a unique identifier that represents the object to which the e-tag is attached. When the electronic tag receives the reader's transmit signal, the electronic tag is “awake”, and then the corresponding action is completed according to the instructions transmitted by the reader, and the response information is transmitted back to the reader. The storage unit on the electronic tag can read and write more than 10,000 times.
The reader can also be subdivided into reader antennas and readers. The reader “wakes up” and transmits instructions to the electronic tag via the reader antenna transmit signal and receives the signal returned by the tag. After the initial filtering and signal processing, the electronic tag information is obtained and parsed, and useful data is exchanged through the network and the data management system.
The data management system mainly completes the storage and management of data information. The data management system can be served by simple local software, or distributed ERP management software that integrates RFID management modules.
The communication process of the RFID system is the process of the reader giving the RFID tag information and obtaining the information on the tag. Since the RFID tag itself has no power source, it must rely on the energy obtained from the radio frequency signal sent by the reader, the so-called beam power supply technology. However, the tag can only use energy to supply the tag itself. There is no excess energy for the RF signal source. Passive reflection modulation technology must be used to achieve communication between the RFID reader and the tag. Passive-reflection modulation technology means that there is only one transmitter, the reader, in the entire communication process of the RFID system. The RFID tag modulates the continuous wave RF signal emitted by the reader during the response process, and then reflects the modulated RF signal back and receives the decoding by the reader to complete the information transmission function. The beam power supply technology and passive reflection modulation technology are two key technologies of the reflective modulation type RFID system.