openHAB - One Wire Bricklet¶

Read DS 18B 20Temperature¶

Download (ExampleReadDS18B20Temperature.rules)

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rule "Read DS18B20 Temperature"
when
    System started // Replace with trigger of your choice
then
    // Change XYZ to the UID of your One Wire Bricklet
    val owActions = getActions("tinkerforge", "tinkerforge:brickletonewire:XYZ")

    owActions.brickletOneWireWriteCommand(0, 78) // WRITE SCRATCHPAD
    owActions.brickletOneWireWrite(0) // ALARM H (unused)
    owActions.brickletOneWireWrite(0) // ALARM L (unused)
    owActions.brickletOneWireWrite(127) // CONFIGURATION: 12-bit mode

    owActions.brickletOneWireWriteCommand(0, 68) // CONVERT T (start temperature conversion)

    createTimer(now.plusSeconds(1), [| // Wait for conversion to finish

        owActions.brickletOneWireWriteCommand(0, 190) // READ SCRATCHPAD

        val tLow = owActions.brickletOneWireRead().get("data") as int
        val tHigh = owActions.brickletOneWireRead().get("data") as int

        var float temperature = tLow + (tHigh * 256)

        // Negative 12-bit values are sign-extended to 16-bit two's complement
        if (temperature > 4096) {
            temperature = temperature - 65536
        }

        // 12-bit mode measures in units of 1/16°C
        logInfo("Example", "Temperature: " + temperature / 16.0 + "°C")
    ])
end

Basic Actions¶

brickletOneWireSearchBus()¶

Return Map:	identifier – Type: long[], Length: variable, Range: [0 to 264 - 1] status – Type: int, Range: See constants

Returns a list of up to 64 identifiers of the connected 1-Wire devices. Each identifier is 64-bit and consists of 8-bit family code, 48-bit ID and 8-bit CRC.

To get these identifiers the Bricklet runs the SEARCH ROM algorithm, as defined by Maxim.

The following constants are available for this function:

For status:

• val STATUS_OK = 0
• val STATUS_BUSY = 1
• val STATUS_NO_PRESENCE = 2
• val STATUS_TIMEOUT = 3
• val STATUS_ERROR = 4

brickletOneWireResetBus()¶

Return Map:	status – Type: int, Range: See constants

Resets the bus with the 1-Wire reset operation.

The following constants are available for this function:

For status:

• val STATUS_OK = 0
• val STATUS_BUSY = 1
• val STATUS_NO_PRESENCE = 2
• val STATUS_TIMEOUT = 3
• val STATUS_ERROR = 4

brickletOneWireWrite(int data)¶

Parameters:	data – Type: int, Range: [0 to 255]
Return Map:	status – Type: int, Range: See constants

Writes a byte of data to the 1-Wire bus.

The following constants are available for this function:

For status:

• val STATUS_OK = 0
• val STATUS_BUSY = 1
• val STATUS_NO_PRESENCE = 2
• val STATUS_TIMEOUT = 3
• val STATUS_ERROR = 4

brickletOneWireRead()¶

Return Map:	data – Type: int, Range: [0 to 255] status – Type: int, Range: See constants

Reads a byte of data from the 1-Wire bus.

The following constants are available for this function:

For status:

• val STATUS_OK = 0
• val STATUS_BUSY = 1
• val STATUS_NO_PRESENCE = 2
• val STATUS_TIMEOUT = 3
• val STATUS_ERROR = 4

brickletOneWireWriteCommand(long identifier, int command)¶

Parameters:	identifier – Type: long, Range: [0 to 264 - 1] command – Type: int, Range: [0 to 255]
Return Map:	status – Type: int, Range: See constants

Writes a command to the 1-Wire device with the given identifier. You can obtain the identifier by calling SearchBus(). The MATCH ROM operation is used to write the command.

If you only have one device connected or want to broadcast to all devices you can set the identifier to 0. In this case the SKIP ROM operation is used to write the command.

The following constants are available for this function:

For status:

• val STATUS_OK = 0
• val STATUS_BUSY = 1
• val STATUS_NO_PRESENCE = 2
• val STATUS_TIMEOUT = 3
• val STATUS_ERROR = 4

Advanced Actions¶

brickletOneWireGetCommunicationLEDConfig()¶

Return Map:	config – Type: int, Range: See constants, Default: 3

Returns the configuration as set by the thing configuration

The following constants are available for this function:

For config:

• val COMMUNICATION_LED_CONFIG_OFF = 0
• val COMMUNICATION_LED_CONFIG_ON = 1
• val COMMUNICATION_LED_CONFIG_SHOW_HEARTBEAT = 2
• val COMMUNICATION_LED_CONFIG_SHOW_COMMUNICATION = 3

brickletOneWireGetChipTemperature()¶

Return Map:	temperature – Type: int, Unit: 1 °C, Range: [-215 to 215 - 1]

Returns the temperature as measured inside the microcontroller. The value returned is not the ambient temperature!

The temperature is only proportional to the real temperature and it has bad accuracy. Practically it is only useful as an indicator for temperature changes.

brickletOneWireGetStatusLEDConfig()¶

Return Map:	config – Type: int, Range: See constants, Default: 3

Returns the configuration as set by the thing configuration

The following constants are available for this function:

For config:

• val STATUS_LED_CONFIG_OFF = 0
• val STATUS_LED_CONFIG_ON = 1
• val STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
• val STATUS_LED_CONFIG_SHOW_STATUS = 3

brickletOneWireGetSPITFPErrorCount()¶

Return Map:	errorCountAckChecksum – Type: long, Range: [0 to 232 - 1] errorCountMessageChecksum – Type: long, Range: [0 to 232 - 1] errorCountFrame – Type: long, Range: [0 to 232 - 1] errorCountOverflow – Type: long, Range: [0 to 232 - 1]

Returns the error count for the communication between Brick and Bricklet.

The errors are divided into

• ACK checksum errors,
• message checksum errors,
• framing errors and
• overflow errors.

The errors counts are for errors that occur on the Bricklet side. All Bricks have a similar function that returns the errors on the Brick side.

brickletOneWireReset()¶

Calling this function will reset the Bricklet. All configurations will be lost.

After a reset you have to create new device objects, calling functions on the existing ones will result in undefined behavior!

brickletOneWireGetIdentity()¶

Return Map:

uid – Type: String, Length: up to 8 connectedUid – Type: String, Length: up to 8 position – Type: char, Range: ['a' to 'h', '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). A Bricklet connected to an Isolator Bricklet is always at position 'z'.

The device identifier numbers can be found here. 

Internal Actions¶

brickletOneWireReadUID()¶

Return Map:	uid – Type: long, Range: [0 to 232 - 1]

Returns the current UID as an integer. Encode as Base58 to get the usual string version.