In order to simplify installation and operation, modern home security systems must be able to monitor home environment wirelessly. This includes monitoring peripheral security, intrusion detection, and the security of sensitive areas of the home such as medicine containers, safes, or other valuables hideouts.
Although video surveillance is feasible, it requires sophisticated image processing and analysis to detect unauthorized activities, which also raises privacy concerns. Traditional motion sensors solve the privacy problem, but they require power and supporting electronic equipment, which increases the BOM cost of the product. In addition, the motion sensor also needs some kind of wired or wireless interface to relay the output of the sensor to the cloud. In many cases, cameras and motion sensors require professional installation, which makes them uneconomical for many cost-sensitive applications.
RFID tags can be used as the basis for a series of powerful security sensors. Integrate the RFID tag with the reed switch then a motion sensor can be made. Similarly, a reed switch can be used instead of a shock switch to make a shock sensor. In both cases, the sensor switch is connected between the antenna and the two ends of the RFID chip. In this configuration, the operation of the RFID tag is enabled or disabled according to the ON or OFF state of the switch.
How the sensor works
1. The vibration sensor is composed of RFID chip, antenna and vibration sensor
(a). In the normal (undisturbed) state, the metal ball will short-circuit the two contacts of the shock sensor.
(b). When the sensor is disturbed, its metal ball no longer short-circuits the two contacts, so that the antenna can receive the power of the RFID chip and transmit its signal (c).
2. The motion sensor is composed of RFID chip, antenna and reed switch (d).
In the normal state, the reed switch is kept in the ON state by a magnet attached nearby. This short-circuits the antenna and prevents the RFID chip from receiving power (e). After removing the magnet, the reed switch is switched to the OFF state, thereby activating the RFID device (f).
RFID technology is a very promising tool that can create powerful, reliable and low-cost security systems. The label is easy to install and does not require batteries, ensuring its long-term reliability. However, in actual applications, care must be taken to ensure that the location where the RFID reader is installed can completely cover the monitored area. Further commercialization also requires the development of "smart" RFID readers so that at least the first level of processing can be performed on the activities generated by RFID tags.