Documentation for RFID Tag Reader

Circuit Diagram for RFID Reader in, RS-232 out

This circuit design enables the RI-STU-MRD1 Micro Reader to communicate with a computer or other device using the RS-232 protocol. The DS275 chip changes the 5 volts communications signal from the Micro Reader to a standard 12 volts. Connected between pins 16 and 19 on the Micro Reader is a Dynasys P-7896 antennae. The status of the antennae is shown via the LED connected to pin 30. If the antennae is active the pin will go low, turning the LED off, else it will be high. The LED connected to pin 29 goes high to signal a successful tag read.

RFID Board Design

Download Express PCB File

Two RFID boards are combined onto a single board to take advantage of ExpressPCB’s cheaper mini board prices. Power is connected to the board using 3.5mm audio jacks. There is a surface mounted jack on one side of the board and a panel mounted one on the other. This enables meeper receiver stations and RFID tag readers to be easily chained together, thus needing only one power supply for several boards. The communications port on this board is a RJ-11 style connector, which is the same as on the meeper receiver station. This is much more compact for communications between the RFID tag reader and the meeper receiver station, and can be connected to a DB-9 connector using an adapter. Pin 2 on the RJ-11 connector is set up for transmit and pin 5 is receive. Pins 3 and 4 are tied to ground.

More info on RFID technology can be found at www.tiris.com

This circuit design is an adaptation of work originally done by Alireza Veiseh.