openHAB - NFC/RFID Bricklet

This is the description of the openHAB API bindings for the NFC/RFID Bricklet. General information and technical specifications for the NFC/RFID Bricklet are summarized in its hardware description.

An installation guide for the openHAB API bindings is part of their general description.

Examples

The example code below is Public Domain (CC0 1.0).

Scan For Tags

Download (ExampleScanForTags.rules)

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// For this example create an item linked to the state channel of your NFC RFID Bricklet.

import java.util.List;
import java.util.stream.Collectors;

val READER_STATE_IDLE = 128
val READER_STATE_REQUEST_TAG_ID_READY = 130
val READER_STATE_REQUEST_TAG_ID_ERROR = 194

val TAG_TYPE_TYPE2 = 2

rule "NFC"
when
    // Change XYZ_State to the created item name
    Item XYZ_State changed
then
    val stateVal = XYZ_State.state as Number
    val int state = stateVal.intValue

    // Change XYZ to the UID of your NFC RFID Bricklet
    val nfc = getActions("tinkerforge", "tinkerforge:brickletnfcrfid:XYZ")

    if (state == READER_STATE_IDLE || state == READER_STATE_REQUEST_TAG_ID_ERROR) {
        nfc.brickletNFCRFIDRequestTagID(TAG_TYPE_TYPE2)
    } else if (state == READER_STATE_REQUEST_TAG_ID_READY) {
        logInfo("Example", "tag id ready")
        
        val ret = nfc.brickletNFCRFIDGetTagID()
        
        val tagType = ret.get("tagType")
        val tagID = ret.get("tid") as List<Short>
        val tagLength = ret.get("tidLength")
        
        val tag = String.join(" ", tagID.stream().limit(tagLength).map([i | String.format("0x%02X", i)]).collect(Collectors.toList()));
        
        logInfo("Example", "tag id:" + tag)
        
        // Read tag ID again in one second.
        createTimer(now.plusSeconds(1), [|nfc.brickletNFCRFIDRequestTagID(2 as short)])
    }
end

Thing

UID:
  • tinkerforge:brickletnfcrfid:[UID]
Required firmware version:
  • 2.0.0
Firmware update supported:
  • yes
Channels:
Actions:

Channels

State

The current state of the bricklet. Calling actions is only allowed in idle, ready and error states (e.g. all states >= 128). The following states are defined:

  • STATE_INITIALIZATION = 0
  • STATE_IDLE = 128
  • STATE_ERROR = 192
  • STATE_REQUEST_TAG_ID = 2
  • STATE_REQUEST_TAG_ID_READY = 130
  • STATE_REQUEST_TAG_ID_ERROR = 194
  • STATE_AUTHENTICATING_MIFARE_CLASSIC_PAGE = 3
  • STATE_AUTHENTICATING_MIFARE_CLASSIC_PAGE_READY = 131
  • STATE_AUTHENTICATING_MIFARE_CLASSIC_PAGE_ERROR = 195
  • STATE_WRITE_PAGE = 4
  • STATE_WRITE_PAGE_READY = 132
  • STATE_WRITE_PAGE_ERROR = 196
  • STATE_REQUEST_PAGE = 5
  • STATE_REQUEST_PAGE_READY = 133
  • STATE_REQUEST_PAGE_ERROR = 197
Type:
  • Number:Dimensionless
UID:
  • tinkerforge:brickletnfcrfid:[UID]:BrickletNFCRFIDState
Read only:
  • Yes

Actions

Actions can be used in rules by creating an action object. All actions return a Map<String, Object>. Returned values can be accessed by name, sometimes the type deduction needs some hints, as shown below:

val actions = getActions("tinkerforge", "tinkerforge:brickletnfcrfid:[UID]")
val hwVersion = actions.brickletNFCRFIDGetIdentity().get("hardwareVersion") as short[]
logInfo("Example", "Hardware version: " + hwVersion.get(0) + "." + hwVersion.get(1) + "." + hwVersion.get(2))

Basic Actions

brickletNFCRFIDRequestTagID(short tagType)
Parameters:
  • tagType – Type: short, Range: See constants

To read or write a tag that is in proximity of the NFC/RFID Bricklet you first have to call this function with the expected tag type as parameter. It is no problem if you don't know the tag type. You can cycle through the available tag types until the tag gives an answer to the request.

Currently the following tag types are supported:

  • Mifare Classic
  • NFC Forum Type 1
  • NFC Forum Type 2

After you call RequestTagID() the NFC/RFID Bricklet will try to read the tag ID from the tag. After this process is done the state will change. You can either register the State channel or you can poll State to find out about the state change.

If the state changes to RequestTagIDError it means that either there was no tag present or that the tag is of an incompatible type. If the state changes to RequestTagIDReady it means that a compatible tag was found and that the tag ID could be read out. You can now get the tag ID by calling GetTagID().

If two tags are in the proximity of the NFC/RFID Bricklet, this function will cycle through the tags. To select a specific tag you have to call RequestTagID() until the correct tag id is found.

In case of any Error state the selection is lost and you have to start again by calling RequestTagID().

The following constants are available for this function:

For tagType:

  • val TAG_TYPE_MIFARE_CLASSIC = 0
  • val TAG_TYPE_TYPE1 = 1
  • val TAG_TYPE_TYPE2 = 2
brickletNFCRFIDGetTagID()
Return Map:
  • tagType – Type: short, Range: See constants
  • tidLength – Type: short, Range: [4, 7]
  • tid – Type: short[], Length: 7, Range: [0 to 255]

Returns the tag type, tag ID and the length of the tag ID (4 or 7 bytes are possible length). This function can only be called if the NFC/RFID is currently in one of the Ready states. The returned ID is the ID that was saved through the last call of RequestTagID().

To get the tag ID of a tag the approach is as follows:

  1. Call RequestTagID()
  2. Wait for state to change to RequestTagIDReady (see State or State channel)
  3. Call GetTagID()

The following constants are available for this function:

For tagType:

  • val TAG_TYPE_MIFARE_CLASSIC = 0
  • val TAG_TYPE_TYPE1 = 1
  • val TAG_TYPE_TYPE2 = 2
brickletNFCRFIDGetState()
Return Map:
  • state – Type: short, Range: See constants
  • idle – Type: boolean

Returns the current state of the NFC/RFID Bricklet.

On startup the Bricklet will be in the Initialization state. The initialization will only take about 20ms. After that it changes to Idle.

The functions of this Bricklet can be called in the Idle state and all of the Ready and Error states.

Example: If you call RequestPage(), the state will change to RequestPage until the reading of the page is finished. Then it will change to either RequestPageReady if it worked or to RequestPageError if it didn't. If the request worked you can get the page by calling GetPage().

The same approach is used analogously for the other API functions.

The following constants are available for this function:

For state:

  • val STATE_INITIALIZATION = 0
  • val STATE_IDLE = 128
  • val STATE_ERROR = 192
  • val STATE_REQUEST_TAG_ID = 2
  • val STATE_REQUEST_TAG_ID_READY = 130
  • val STATE_REQUEST_TAG_ID_ERROR = 194
  • val STATE_AUTHENTICATING_MIFARE_CLASSIC_PAGE = 3
  • val STATE_AUTHENTICATING_MIFARE_CLASSIC_PAGE_READY = 131
  • val STATE_AUTHENTICATING_MIFARE_CLASSIC_PAGE_ERROR = 195
  • val STATE_WRITE_PAGE = 4
  • val STATE_WRITE_PAGE_READY = 132
  • val STATE_WRITE_PAGE_ERROR = 196
  • val STATE_REQUEST_PAGE = 5
  • val STATE_REQUEST_PAGE_READY = 133
  • val STATE_REQUEST_PAGE_ERROR = 197
brickletNFCRFIDAuthenticateMifareClassicPage(int page, short keyNumber, short[] key)
Parameters:
  • page – Type: int, Range: [0 to 216 - 1]
  • keyNumber – Type: short, Range: See constants
  • key – Type: short[], Length: 6, Range: [0 to 255]

Mifare Classic tags use authentication. If you want to read from or write to a Mifare Classic page you have to authenticate it beforehand. Each page can be authenticated with two keys: A (key_number = 0) and B (key_number = 1). A new Mifare Classic tag that has not yet been written to can be accessed with key A and the default key [0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF].

The approach to read or write a Mifare Classic page is as follows:

  1. Call RequestTagID()
  2. Wait for state to change to RequestTagIDReady (see State or State channel)
  3. If looking for a specific tag then call GetTagID() and check if the expected tag was found, if it was not found go back to step 1
  4. Call AuthenticateMifareClassicPage() with page and key for the page
  5. Wait for state to change to AuthenticatingMifareClassicPageReady (see State or State channel)
  6. Call RequestPage() or WritePage() to read/write page

The following constants are available for this function:

For keyNumber:

  • val KEY_A = 0
  • val KEY_B = 1
brickletNFCRFIDWritePage(int page, short[] data)
Parameters:
  • page – Type: int, Range: [0 to 216 - 1]
  • data – Type: short[], Length: 16, Range: [0 to 255]

Writes 16 bytes starting from the given page. How many pages are written depends on the tag type. The page sizes are as follows:

  • Mifare Classic page size: 16 byte (one page is written)
  • NFC Forum Type 1 page size: 8 byte (two pages are written)
  • NFC Forum Type 2 page size: 4 byte (four pages are written)

The general approach for writing to a tag is as follows:

  1. Call RequestTagID()
  2. Wait for state to change to RequestTagIDReady (see State or State channel)
  3. If looking for a specific tag then call GetTagID() and check if the expected tag was found, if it was not found got back to step 1
  4. Call WritePage() with page number and data
  5. Wait for state to change to WritePageReady (see State or State channel)

If you use a Mifare Classic tag you have to authenticate a page before you can write to it. See AuthenticateMifareClassicPage().

brickletNFCRFIDRequestPage(int page)
Parameters:
  • page – Type: int, Range: [0 to 216 - 1]

Reads 16 bytes starting from the given page and stores them into a buffer. The buffer can then be read out with GetPage(). How many pages are read depends on the tag type. The page sizes are as follows:

  • Mifare Classic page size: 16 byte (one page is read)
  • NFC Forum Type 1 page size: 8 byte (two pages are read)
  • NFC Forum Type 2 page size: 4 byte (four pages are read)

The general approach for reading a tag is as follows:

  1. Call RequestTagID()
  2. Wait for state to change to RequestTagIDReady (see State or State channel)
  3. If looking for a specific tag then call GetTagID() and check if the expected tag was found, if it was not found got back to step 1
  4. Call RequestPage() with page number
  5. Wait for state to change to RequestPageReady (see State or State channel)
  6. Call GetPage() to retrieve the page from the buffer

If you use a Mifare Classic tag you have to authenticate a page before you can read it. See AuthenticateMifareClassicPage().

brickletNFCRFIDGetPage()
Return Map:
  • data – Type: short[], Length: 16, Range: [0 to 255]

Returns 16 bytes of data from an internal buffer. To fill the buffer with specific pages you have to call RequestPage() beforehand.

Advanced Actions

brickletNFCRFIDGetIdentity()
Return Map:
  • uid – Type: String, Length: up to 8
  • connectedUid – Type: String, Length: up to 8
  • position – Type: char, Range: ['a' to 'h', 'i', 'z']
  • hardwareVersion – Type: short[], Length: 3
    • 0: major – Type: short, Range: [0 to 255]
    • 1: minor – Type: short, Range: [0 to 255]
    • 2: revision – Type: short, Range: [0 to 255]
  • firmwareVersion – Type: short[], Length: 3
    • 0: major – Type: short, Range: [0 to 255]
    • 1: minor – Type: short, Range: [0 to 255]
    • 2: revision – Type: short, Range: [0 to 255]
  • deviceIdentifier – Type: int, Range: [0 to 216 - 1]

Returns the UID, the UID where the Bricklet is connected to, the position, the hardware and firmware version as well as the device identifier.

The position can be 'a', 'b', 'c', 'd', 'e', 'f', 'g' or 'h' (Bricklet Port). The Raspberry Pi HAT (Zero) Brick is always at position 'i' and the Bricklet connected to an Isolator Bricklet is always as position 'z'.

The device identifier numbers can be found here