Connecting RFID reader with RS232 interface to an arduino

Question

I am attempting to detect 134.2kHz RFID tags using a chip from Priority 1 Design, specifically this one

I am attempting to connect this to an arduino Uno, but I am not really sure where to start. There appear to be some instructions here on how to read and write data to an RS232 interface RS232 interface, however I was wondering if I need to do this? There are tx and rx pins on the board as well, but I don't seem to be able to find any details on what kind of output those pins produce? Do I need to communicate to these additional ports using RS232?

Answer 1

Your Arduino's microcontroller has a UART (Universal Asyncronious Receiver/Transmitter) which can be programmed to be connected to a pair of pins on the board. This uses the same signals as your RFID reader, except at different voltage levels (and inversion). To connect the two, you need a converter, as described in the link you provided.

If you were to directly connect the RFID reader to your Arduino, you would probably damage the Arduino due to the voltage differences.

If you don't want to breadboard the circuit, you could use something like http://www.cutedigi.com/arduino-shields/rs232-shield-for-arduino.html

Answer 2

If your device requires true RS232 levels, an ideal solution would be one of the older Arduino designs which was equipped with an RS232 serial connection instead of the USB-serial connection of the modern Arduino-style boards. The older board might have originally had a smaller Atmega part such as a 168 or even 88, but you should be able to substitute in the more recent Atmega328p if you need its memory, independent of the serial circuitry on the board.