Designing a high performance RAIN RFID reader is not an easy job. Even if today you can choose a chipset platform on the market that implements most of the needed features and build the reader around it, you still have to face with many technical details, especially regarding the correct handling of Ultra High Frequency signals. So, even if you don’t need to know every detail of the RAIN RFID air protocol, you still need very good radio frequency skills to obtain good reading performances and to comply with regulations.
Reading tags at long distances requires two main things: generate a high power signal to “activate” the tags and a good receiver sensitivity in order to be able to “intercept” the very small signals reflected by the tags but none of the two come for free. To generate high power levels you need to add a power amplifier (and other circuitry) between the chipset output and the antenna connector and assure that the resulting signal is clean enough in order to avoid interferences, to comply with regulations and to avoid the self jamming effect. All these aspects require high radiofrequency skills for the design and a specific care on the manufacturing of the PCB (Printed Circuit Board).
But, if you are looking to build a RAIN RFID reader or to embed the technology in your device, there is a simpler way. CAEN RFID designed the Hadron (R4320C) module, a complete high performance RAIN RFID reader in a compact form factor. The module solves internally all the complexity of the RF design offering 4 anten able to provide up to 31.5dBm (1.4W) of power and serial and USB interface for a simple communication with the controller.
So, combining the Hadron module with a computing platform, you can design a smart and high performance RAIN RFID reader with limited design efforts. Depending on the project, the computing platform can be custom designed or chosen from the many available on the market, such as an Arduino, a Raspberry or a BeagleBone just to cite some of the well-known ones. The communication between the computing platform and the Hadron module via the USB interface is fast and easy to implement but, if the CPU does not include an USB host interface (like it could be for a small microprocessor), the module can be fully controlled using a serial line compatible with a direct connection to the microcontrollers (TTL levels).
To further simplify the integration and control of the Hadron module, CAEN RFID provides a complete SDK for the most common programming languages (Java, .NET and C) so that you don’t need to write the code for the protocol interpretation but just the code for the solution. Furthermore CAEN RFID offer in depth technical support on both hardware and software topics as well as support for the certification process of your product using its modules.
 the protocol used by readers and tags to communicate each other
 passive RAIN RFID tags have no power source to generate signals so they use a technology called backscatter that use signal reflections to communicate with the reader
 self-generated noise that create problems with the receiver part of the reader