Posted on by tigoe

Sonmicro RFID Reader Library for Processing

Last year, I worked with Timo Arnall and Einar Martinussen and Jørn Knutsen on a Processing library to read and write to Mifare RFID tags using the Sonmicro SM130 read/write module.  Here it is, with a few improvements and bug fixes.

SonMicroReader.zip

To use the library, unzip it and copy the folder to your Processing libraries folder.  Then restart Processing.  There are two example sketches, a simple reader that seeks new tags, and a full read/write example.

For more details, see the datasheet for the module. Code examples will follow in this blog.

The available commands are as follows:

SonMicroReader(PApplet p, Serial s) – initializes a new instance of the library

Example:

import processing.serial.*;
import sonMicroReader.*;
Serial myPort;                // serial port instance
SonMicroReader myReader;      // sonMicroReader instance 

void setup() {
  // set window size:
  size(400,300);
  // based on the list of serial ports printed from the
  // previous command, change the 0 to your port's number:
  String portnum = Serial.list()[0];
  // initialize the serial port. default data rate for
  // the SM130 reader is 19200:
  myPort = new Serial(this, portnum, 19200);
  // initialize the reader instance:
  myReader = new SonMicroReader(this,myPort);
  myReader.start();
  myReader.reset();
}

void start() – Starts the reader instance. Spawns a new thread to continually scan for new serial data, and generates a sonMicroEvent() when a new packet is received.
Example:

  myReader.start();

void quit() – stops the reader instance
Example:

  myReader.quit();

boolean available() – returns whether or not there’s an availble data packet

Example:

if (myReader.available() {
 int[] newReading = myReader.sonMicroReading();
 println(newReading();
}

int[] getSonMicroReading() – Used mainly for debugging, this method returns all the bytes that come in from the reader. Returns an array of all the bytes from the reader in response to a given command.

Example:

int[] newReading = myReader.sonMicroReading();

int getCommand()– returns the command byte as received by the reader
Example:

int lastCommand = myReader.getCommand();

int getPacketLength() – returns the length of the payload as reported by the reader
Example:

int packetLength = myReader.getPacketLength();

int getCheckSum() – returns the checksum from the reader

Example:

int checksum = myReader.getCheckSum();

int[] getPayload() – returns the array of bytes in the payload of the message

Example:

int[] payLoad = myReader.getPayload();

int[] getTagNumber() – returns the array of bytes in the tag number of the message

Example:

int[] tagNumber = myReader.getTagNumber();

String getTagString() – returns the ASCII-encoded hex string of the tag number of the message

Example:

String tagString = myReader.getTagString();

int getTagType() – Assuming there’s a valid tag read, this returns the tag type, as follows:

  • 0x01 Mifare Ultralight
  • 0x02 Mifare Standard 1K
  • 0x03 Mifare Classic 4K
  • 0xFF Unknown Tag type

Example:

int tagType = myReader.getTagType();

void reset() –  Resets the reader by sending command 0x80
Example:

myReader.reset();

void getFirmwareVersion() – gets the firmware of the reader by sending command 0x81

Example:

myReader.getFirmWareVersion();

int getErrorCode() – Gets the error code returned by some messages, as follows:

Example:

int errorCode = myReader.getErrorCode();

Select Tag (command 0x83)

  • 0x4E ‘N’ No Tag present.
  • 0x55 ‘U’ Access failed due to RF Field is OFF

Seek for Tag (command 0x82)

  • 0x4C  ‘L’ Command in progress.
  • 0x55 ‘U’ Command in progress but RF Field is OFF

Authenticate (command 0x85)

  • 0x4C ‘L’ Login Successful
  • 0x4E ‘N’ No Tag present or Login Failed
  • 0x55 ‘U’ Login Failed
  • 0x45 ‘E’ Invalid key format in E2PROM

Read Block (command 0x86)

  • 0x4E ‘N’ No Tag present
  • 0x46 ‘F’ Read Failed

Read Value Block (command 0x87)

  • 0x4E ‘N’ No Tag present
  • 0x49 ‘I’ Invalid Value Block
  • 0x46 ‘F’ Read Failed

Write Block (command 0x89)

  • 0x55 ‘U’ Read after write failed
  • 0x58 ‘X’ Unable to Read after write
  • 0x4E ‘N’ No Tag present
  • 0x46 ‘F’ Write Failed

Write Value Block (command 0x8A)

  • 0x4E ‘N’ No Tag present
  • 0x49 ‘I’ Invalid Value Block. The block was not in the proper value format when read back. This could be because there was an error in writing
  • 0x46 ‘F’ Read Failed during verification

Write 4-byte block (command 0x8B)

  • 0x55 ‘U’ Read after write failed
  • 0x58 ‘X’ Unable to Read after write
  • 0x4E ‘N’ No Tag present
  • 0x46 ‘F’ Write Failed

Write Master Key (command 0x8C)

  • 0x4C ‘L’  Write Master key successful
  • 0x4E ‘N’  Write Master key fail

Set Antenna Power (command 0x90)

  • 0x00 RF Field switched Off
  • 0x01 RF Field switched On

Set Baud Rate (command 0x94)

  • 0x4C ‘L’ Change of Baud rate successful
  • 0x4E ‘N’ Change of Baud rate failed
  • @return  an int for the error code.

String getErrorMessage() – returns a descriptive error message

Example:

String errorMsg = myReader.getErrorMessage();

int getAntennaPower() – returns  the antenna power. 0x00 is off, anything else is on

Example:

int antennaPower = myReader.getAntennaPower();

void seekTag() – Sends the Seek Tag command (0x83)

Example:

myReader.seekTag();

void selectTag()– Sends the Select Tag command (0x82)

Example:

myReader.selectTag();

void setAntennaPower(int level) – Sets the antenna power.  0x00 is off, anything else is on

Example:

myReader.setAntennaPower(1);  // turns antenna on

void sleep() – Sends the sleep command (0x96)

Example:

myReader.sleep();

void setBaudRate(int baudRate) – sets the baud rate. Possible baud rates:

  • 9600 bps
  • 19200 bps
  • 38400 bps
  • 57600 bps
  • 115200 bps

Example:

myReader.setBaudRate(57600);

void writeBlock(int thisBlock, String thisMessage) – Writes a 16-byte string to a block. If the string is less than 16 bytes, it fills the empty bytes with 0x00.  If more than 16 bytes, it generates an error message. You need to select and authenticate before you can read or write.

Example:

myReader.writeBlock(0x10, "Hello World!");

public void writeFourByteBlock(int thisBlock, String thisMessage) – Writes a 4-byte string to a block. If the string is less than 16 bytes, it fills the empty bytes with 0x00.  If more than 4 bytes, it generates an error message. Used for Mifare ultralight tags. You need to select and authenticate before ou can read or write.

Example:

  myReader.writeFourByteBlock(0x10, "Beep");

void authenticate(int thisBlock, int authentication) – Authenticates for reading and writing. You need to select and authenticate before you can read or write.

  • thisBlock: Block to write to
  • authentication: Authentication type to use (see SM130 datasheet for more; as a default, use 0xFF)

Example:

  myReader.authenticate(0x10, 0xFF);

void readBlock(int thisBlock) – Reads a block of data. You need to select and authenticate before you can read or write. You need to select and authenticate before ou can read or write.

  • thisBlock:  Block to read from

Example:

 myReader.readBlock(0x10);

void sendCommand(int thisCommand) – Sends a single-byte command

Example:

 myReader.sendCommand(0x80);  // resets the module

void sendCommand(int[] thisCommand) – Sends a multi-byte command

Example:

 int[] thisCommand = {0x90, 0x01};   // setAntenna, power level 1
 myReader.sendCommand(thisCommand);

int version() – returns the version number of the library

Example:

 println(myReader.version());

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