Application of RFID technology in home-school communications

The collection of student and teacher information is a core part of the "Home-School Communication" system. How to correctly identify students entering school and accurately send safe text messages to parents is the key. Nowadays, system integrators generally use RFID radio frequency identification technology. When students carry electronic cards through the school gate, the devices placed around the school gate sense the information and report it to the software, completing an information collection process. At present, rfid technology is developing rapidly, and the technical scope is also relatively broad. The rfid technologies that can be applied in "home-school communication" are roughly divided into low frequency, high frequency, ultra high frequency, active 2.4g and other rfid technologies. Each technology category also differs in application according to its own characteristics. The following is a summary of the application methods and advantages of each technology in "Home-School Connect".

Application of RFID technology in home-school communications

1. Low frequency

The working frequency of low-frequency rfid is 125khz, and the device type adopts channel mode. Students wear cards and can automatically read information through the channel. Due to the limitation of low-frequency reading distance, the distance between low-frequency channels is about 80cm. The speed of people passing through the low-frequency rfid channel is not ideal. Since the low-frequency channel cannot support reading multiple tags at the same time, only one person is allowed to pass through the channel at a time. This obviously cannot meet the needs of the school during the peak period. Department integrators use multiple sets of channels to alleviate this problem. The advantage of low-frequency RFID is that the low frequency is basically not affected by water and liquids, and the human body wearing the tag will not affect the channel's reading effect on the card. The channel's reading of information can be locked to individuals, and alarms can be issued for people without cards. This can prevent students from entering without a card or outsiders entering the campus. In addition, low-frequency RFID tags are relatively cheap. According to its own technical characteristics, low-frequency rfid technology is more used in livestock management in animal husbandry. On the one hand, the cost is not high, on the other hand, livestock are large and move slowly. One tag can be read at a time in the low-frequency channel. The form is completely satisfying.

2. High frequency and close range

The frequency band of high-frequency rfid is 13.56mhz, which is divided into two types, one of which is the short-range 14443 protocol. The reading distance of this technology is about 10cm. In the use of "home-school communication", students usually use wall-mounted attendance machines to actively swipe their cards, and barrier-free channels are also used. Of course, if you use a wall-mounted machine, you cannot alarm someone without a card. Therefore, when applying high-frequency rfid at short distances, some businesses also use channels. Because people need to stay and actively swipe their cards, the technical adoption speed of short-range high-frequency RFID is slower than that of low-frequency RFID. However, short-range high-frequency RFID has better security, so it is more commonly used in universities or corporate campuses when it comes to catering and bathing consumption. The card information miss rate is basically the smallest among all technologies.

3. High frequency and long distance

The 15693 protocol is another 13.56mhz high-frequency RFID protocol. The difference between this protocol and 14443 is that it can read at a longer distance. High-frequency and long-distance ones are more commonly used in "home-school communication" and are read using channels. The placement distance of the channel is between 1 meter and 1.2 meters. The reason why high-frequency long-distance rfid is widely used is that some manufacturers have produced channels that can be cascaded. It can use three pieces of equipment to form a dual channel or four pieces of equipment. Three channels can be formed. The more channels placed, the less equipment used. The placement of extra-wide school gates can greatly save costs. In addition, the high-frequency long-distance channel can support multiple tag readings in the channel, and the traffic speed has been greatly improved. In addition, high-frequency and long-distance information can be locked to individuals, and timely alarms can be issued for the entry of people without cards. Effectively prevent outsiders from entering the campus. However, one problem with high-frequency long-distance rfid is that the price of the card is slightly high.

4. Ultra high frequency

The UHF frequency commonly used in China is 915mhz. It is different from the technical principles of low frequency and high frequency. It senses through the principle of signal reflection. Therefore, its reading distance is relatively long, usually the nominal distance of an UHF card reader is 5-15 meters. UHF channels can often be very wide, allowing multiple people to pass side by side. However, at present, UHF has basically no application in "home-school communication". The main reason for this situation is that UHF signals cannot penetrate water, and the human body will absorb a lot of energy when wearing UHF cards. At the same time, UHF reading requires that the card must be at a certain angle with the antenna. When people enter or exit, they will not walk directly towards the antenna in a disciplined manner. It is very likely that the card will be missed if they turn sideways, causing leakage. The reading rate is higher. In addition, the UHF reading boundary is not clear, and multiple people wearing cards seriously affect each other. UHF is currently mostly used in the logistics industry.

5. 2.4g active

In addition to high frequency and long distance, there is another 2.4g active technology that is applied in "home-school communication". Its unique feature is that the card has a battery, which makes its reading distance longer by actively transmitting signals. The difference between active 2.4g and high-frequency long-distance applications is that it installs card readers on both sides of the school gate and is not a channel system in the strict sense. In this way, ultra-wide and large school gates can also conveniently carry out personnel entry and exit information. Read. Active 2.4g currently faces two serious problems. One is the life of the battery. Since it is packaged in the card, once the battery is exhausted, students must replace the card. Even if the battery is not exhausted, after using it for a period of time, Later, due to the weakening of power, the transmission signal will also weaken, and the reading effect will be affected. Another problem is that 2.4g active technology, like UHF, is highly directional, and its performance is affected by humidity. A common problem is that the card cannot be held by hand or placed in the bag behind the pants.

To sum up, due to the rapid development of rfid, different technologies are becoming more mature. The applications it targets also include all aspects of life. As a core part of the construction of "safe campus", the development of "home-school connection" has also been promoted by RFID. It is precisely because of the application of RFID technology that we can now improve the safety of children in school. Children are the future of the motherland. How to choose the right technology to achieve "home-school connectivity" is an issue that all integrators and schools must consider.