Class IDxxLA | Meadow.Foundation API website

Remarks

IDxxLA
Status
Source code	GitHub *TODO (not in master yet)
NuGet package	*TODO (not in nuget yet)

The ID-Innovations LA series is a 125KHz RFID reader controlled via serial connection. There are currently 3 variations available: The ID-12LA, the ID-20LA which has a larger antenna and the ID-2LA/ID-3LA, which is the smallest but requires an external antenna.

Purchasing

The LA series is available from the following suppliers:

To use the RFID readers in your designs, the following breakout boards are available:

SparkFun RFID USB Reader has optional breakout pin header
SparkFun RFID Reader Breakout
- Recommend purchasing 2x 2mm sockets to reduce the chance of damaging the RFID readers when soldering

Code Example

The IDxxLA can be consumed though an event or by subscribing as an observer. Both approaches are equally effective and have slightly different usage patterns. It is also possible to read the LastRead property at any time get the last RFID successfully scanned by the device.

Sample projects available on GitHub

Event Approach

public class MeadowApp : App<F7Micro, MeadowApp>
{
    private readonly IRfidReader _rfidReader;

    public MeadowApp()
    {
        _rfidReader = new IDxxLA(Device, Device.SerialPortNames.Com1);
        // subscribe to event
        _rfidReader.RfidRead += RfidReaderOnTagRead;
        _rfidReader.StartReading();
    }

    private void RfidReaderOnTagRead(object sender, RfidReadResult e)
    {
        // event triggers after a complete read, even if unsuccessful
        // e.Status returns whether the read was successful or not
        if (e.Status == RfidValidationStatus.Ok)
        {
            Console.WriteLine($"Tag value is {DebugInformation.Hexadecimal(e.RfidTag)}");
            return;
        }

        Console.WriteLine($"Error {e.Status}");
    }
}

Observable approach

public class MeadowApp : App<F7Micro, MeadowApp>
{
    private readonly IRfidReader _rfidReader;

    public MeadowApp()
    {
        _rfidReader = new IDxxLA(Device, Device.SerialPortNames.Com1);
        // subscribe to IObservable
        _rfidReader.Subscribe(new RfidObserver());
        _rfidReader.StartReading();
    }

    private class RfidObserver : IObserver<byte[]>
    {
        // OnCompleted will only be called if you dispose of the reader
        public void OnCompleted()
        {
            Console.WriteLine("RfidReader has terminated, no more events will be emitted.");
        }

        // 'error' can optionally be cast to RfidValidationException
        public void OnError(Exception error)
        {
            Console.WriteLine(error);
        }

        // Only called on successful reads.
        public void OnNext(byte[] value)
        {
            Console.WriteLine($"Tag value is {DebugInformation.Hexadecimal(value)}");
        }
    }
}

Wiring Example

To wire an LA series RFID reader to your Meadow board, connect the following depending on the breakout board used:

Meadow Pin	RFID Reader Breakout	RFID USB Reader + Breakout Header
`5V`	`VCC`	`VCC`
`GND`	`GND`, `FORM`	`GND`, `GND` (there are 2)
`D13`	`D0`	`TX`

RFID Reader Breakout diagram:

RFID USB Reader + Breakout Header diagram:

Other wiring notes:

If you are using an ID-2LA/ID-3LA, you will need to connect an antenna to the AN1,AN2/ANT,ANT pins (orange wires in above diagrams).
For the reader breakout it is important to connect FORM to GND, as this tells the reader to use the ASCII format. Other formats are not supported.
For the reader breakout a LED can be connected to READ which can be used as an indication of a card being read. This is completely optional. The LED and a 330Ω resistor is included in the above diagram.
All the LA series RFID readers are suitable for 5V, however should also work fine with 3V3.

Characteristic	Locus
Inheritance	System.Object > IDxxLA
Implements	IRfidReader System.IObservable<System.Byte[]> System.IDisposable
Inherited Members	System.Object.ToString() System.Object.Equals(System.Object) System.Object.Equals(System.Object, System.Object) System.Object.ReferenceEquals(System.Object, System.Object) System.Object.GetHashCode() System.Object.GetType() System.Object.MemberwiseClone()
Namespace	Meadow.Foundation.Sensors.Radio.Rfid
Assembly	IDxxLA.dll

Syntax

public class IDxxLA : IRfidReader, IObservable<byte[]>, IDisposable

Constructors

IDxxLA(IIODevice, SerialPortName)

Create an IDxxLA RFID reader

Declaration

public IDxxLA(IIODevice device, SerialPortName serialPortName)

Parameters

Type	Name	Description
IIODevice	device	Device to use
SerialPortName	serialPortName	Port name to use

IDxxLA(ISerialPort)

Create an IDxxLA RFID reader using an existing port.

Declaration

public IDxxLA(ISerialPort serialPort)

Parameters

Type	Name	Description
ISerialPort	serialPort

Remarks

Be sure to use suitable settings when creating the serial port. Default BaudRate and DataBits are exposed as constants.

Fields

BaudRate

Declaration

public const int BaudRate = 9600

Field Value

Type	Description
System.Int32

DataBits

Declaration

public const int DataBits = 7

Field Value

Type	Description
System.Int32

Properties

LastRead

A cached copy of the last successfully read RFID tag.

Declaration

public byte[] LastRead { get; }

Property Value

Type	Description
System.Byte[]	The last read RFID tag.

SerialPort

Declaration

public ISerialPort SerialPort { get; }

Property Value

Type	Description
ISerialPort

Methods

Dispose()

Dispose of this instance.

Declaration

public void Dispose()

StartReading()

Start reading for RFID tags.

Declaration

public void StartReading()

StopReading()

Stop reading for RFID tags.

Declaration

public void StopReading()

Subscribe(IObserver<Byte[]>)

Subscribe to RFID tag reads. Observer will only receive valid reads, with invalid reads triggering an OnError call. OnComplete will be called if this instance is disposed. This call is thread-safe.

Declaration

public IDisposable Subscribe(IObserver<byte[]> observer)

Parameters

Type	Name	Description
System.IObserver<System.Byte[]>	observer	The observer to subscribe

Returns

Type	Description
System.IDisposable	Disposable unsubscriber

Events

BufferOverrun

Exposed BufferOverrun from SerialPort.

Declaration

public event EventHandler BufferOverrun

Event Type

Type	Description
System.EventHandler

RfidRead

Event fired when an RFID tag is read. Check the read status to see if the read was successful.

Declaration

public event RfidReadEventHandler RfidRead

Event Type

Type	Description
RfidReadEventHandler