Battery-free RFID light detector

Paul Boughton

The SHADOW from Farsens SL is a battery-free RFID ambient light detector tag. These tags are compatible with commercial EPC C1G2 readers. It features a LPRS N5AC501085 Light Dependent Resistor (LDR) to detect exposure to light or darkness.

The SHADOW has a 96 bits EPC number, a 32 bit TID and a password protected Kill command. Built in a PCB format, it is available in different sizes. The communication range is up to 1.5 meters and the operating temperatures are from -30°C to +85°C (-22°F to +185°F). 

These ambient light detector tags are available in a variety of antenna design and sizes, depending on the specific application. They can be embedded in a wide variety of materials such as plastics or concrete and they can also be encapsulated in an IP67 or IP68 casing for usage in harsh environments. Evaluation kits are available.

The fact that the detector is fully passive makes it suitable for hardly accessible or restricted areas and those where the use of batteries is not recommended. The SHADOW will never require a battery change, saving the costs associated to maintenance.

SHADOW tags are used in automation applications

SHADOW tags are used in automation applications where exposure to light of tagged assets change during the process. 

Monitoring the changes allows the user to program a variety of procedures based on process time/status and the detector data. They are usually embedded in sealed places where exposure to light is scarce. Having an exposure is an indicator that a specific action is being taken or needs to be taken, depending on the specific application.