RFID Sensors
RFID, or Radio Frequency Identification, is a technology that uses radio waves for data transfer and tagging objects. A RFID system consists of RFID tags, RFID readers, and antennas to facilitate wireless communication.
An RFID sensor is essentially a small integrated circuit (IC), or RFID chip, attached to an antenna. This combo, known as an RFID tag, can be attached to an object that needs to be tracked or identified. RFID tags come in different forms including RFID stickers, passive RFID tags, active RFID tags, and UHF RFID tags.
Passive tags do not have their own power source. Instead, they get activated when they come within the range of the RFID reader. These RFID readers emit radio frequency waves, and when these waves hit the tag's antenna, it induces a current that powers the chip in the tag. The chip then sends back information to the reader via the antenna. Active RFID tags, on the other hand, have their own power source and can transmit data at all times.
RFID tags can also incorporate sensor technology, resulting in RFID sensor tags. These tags can carry sensors such as temperature sensors or other types of sensors that can monitor physical parameters such as pressure, humidity, light, etc. The data from these sensors can be read wirelessly and in real-time, making them a key technology in many applications including supply chain management, inventory tracking, and many more.
More Information about RFID Sensors
Some RFID systems use Ultra High Frequency (UHF) radio waves, with frequency range from 300 MHz to 3 GHz. UHF RFID has a longer read range and can read more tags simultaneously compared to other types of RFID.
RFID technology also allows for flexible hybrid electronics and printed sensors, enabling small form factors and low-cost solutions. This technology can be used in a variety of applications, such as tracking inventory, in the supply chain, in manufacturing, and in many other industries.
The RFID reader and the tags communicate using a wireless communication link. The reader sends out a signal, which the antenna on the RFID tag picks up. The tag uses the energy from that signal to power the chip and send a response back to the reader.
The RFID reader then receives the backscattered signal from the RFID tag and decodes the information. This information can be anything from a unique ID number to more complex sensor information. For instance, an RFID tag might send back information about the temperature or humidity conditions it has been exposed to.
Limit Switch Basics
What are limit switches?
Limit switches are electromechanical switches that operate based on the movement or presence of an object. They are designed to detect the presence of an object using an actuator connected to a series of contacts to detect the presence and proximity or absence of a material or object. When the switch's actuator is moved by an object it will change the state of an electronic contact set. This movement signals that some preset limit has been reached. There are many different ways a switch can be actuated depending on the type of switch that is being used. Some use a roller and lever, some use a button or plunger, while others might use a rotating arm and rod attached to the main body of a switch. The type of switch that is used will largely be dictated by the specific application.
Where are limit switches used?
Limit switches can be used to tally or count items, so that when a limit is reached, the switch will open or close. This open and closing action can be counted by a controller allowing the action to be totalized. Limit switches can be used as safety interlocks to prevent machine parts from moving any further when specific point is reached. Limit switches are also commonly used in larger control systems. For example, when a certain limit is reached, the actuator can deactivate or activate a device to prevent it from malfunctioning.