Android Things RC522
An Android Things libray to control RFID readers based on the RC522 reader.
Based on pi-rc522 by user ondryaso
Features
- Detect MIFARE 1k tags (not tested in other tags)
- Authenticate, read and write to tags
- Change authentication keys and access bits (must be done manually)
- Increment, decrement, transfer and restore for value blocks
- Easier way of changing keys and access bits
Planned features
- Helper functions
- Better error handling
Connections
The connections vary based on the board used.
RST pin is configured programatically.
Raspberry Pi 3
| RC522 Pin | RPi Pin name | RPi Pin number |
|---|---|---|
| SDA | GPIO8, CE0 | 24 |
| SCK | GPIO11, SCKL | 23 |
| MOSI | GPIO10, MOSI | 19 |
| MISO | GPIO9, MISO | 21 |
| GND | GND | 6, 9, 20, 25 |
| RST | Any GPIO pin | -- |
| 3.3V | 3V3V | 1, 17 |
Installing
This library is available at jCenter. To install add this to your module's build.gradle
dependencies {
compile 'com.galarzaa.android-things:rc522:1.0.0'Usage
The use of interruptions is not supported yet.
The RC522 must be polled until a card is found, and then perform any operations you want.
Unfortunately, in Android, the UI thread shouldn't be blocked, so the polling has to be done on a separate thread e.g. AsyncTask, Runnable, etc.
To use the libary, a SpiDevice object must be passed in the constructor, along with a Gpio object for
the RST pin.
Polling state
import com.galarzaa.androidthings.Rc522;
public class MainActivty extends AppCompatActivity{
private Rc522 mRc522;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
PeripheralManagerService pioService = new PeripheralManagerService();
try {
/* Names based on Raspberry Pi 3 */
SpiDevice spiDevice = pioService.openSpiDevice("SPI0.0");
Gpio resetPin = pioService.openGpio("BCM25");
/* Names based on NXP Pico i.MX7D I/O */
SpiDevice spiDevice = pioService.openSpiDevice("SPI3.0");
Gpio resetPin = pioService.openGpio("GPIO5_IO00");
mRc522 = new Rc522(this, spiDevice, resetPin);
} catch (IOException e) {
e.printStackTrace();
}
}
private void readRFid(){
while(true){
boolean success = mRc522.request();
if(!success){
continue;
}
success = mRc522.antiCollisionDetect();
if(!success){
continue;
}
byte[] uid = mRc522.getUid();
mRc522.selectTag(uid);
break;
}
// Factory Key A:
byte[] key = {(byte)0xFF, (byte)0xFF, (byte)0xFF, (byte)0xFF, (byte)0xFF, (byte)0xFF};
// Data that will be written
byte[] newData = {0x0F,0x0E,0x0D,0x0C,0x0B,0x0A,0x09,0x08,0x07,0x06,0x05,0x04,0x03,0x02,0x01,0x00};
// Get the address of the desired block
byte block = Rc522.getBlockAddress(3, 2);
//We need to authenticate the card, each sector can have a different key
boolean result = rc522.authenticateCard(Rc522.AUTH_A, block, key);
if (!result) {
//Authentication failed
return;
}
result = rc522.writeBlock(block, newData);
if(!result){
//Could not write, key might have permission to read but not write
return;
}
//Buffer to hold read data
byte[] buffer = new byte[16];
//Since we're still using the same block, we don't need to authenticate again
result = rc522.readBlock(block, buffer);
if(!result){
//Could not read card
return;
}
//Stop crypto to allow subsequent readings
rc522.stopCrypto();
}
}Contributing
This library is still in development, suggestions, improvements and fixes are welcome. Please submit a pull request