Go - Color Bricklet

This is the description of the Go API bindings for the Color Bricklet. General information and technical specifications for the Color Bricklet are summarized in its hardware description.

An installation guide for the Go API bindings is part of their general description. Additional documentation can be found on godoc.org.

Examples

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

Simple

Download (example_simple.go)

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
package main

import (
    "fmt"
    "github.com/Tinkerforge/go-api-bindings/color_bricklet"
    "github.com/Tinkerforge/go-api-bindings/ipconnection"
)

const ADDR string = "localhost:4223"
const UID string = "XYZ" // Change XYZ to the UID of your Color Bricklet.

func main() {
    ipcon := ipconnection.New()
    defer ipcon.Close()
    c, _ := color_bricklet.New(UID, &ipcon) // Create device object.

    ipcon.Connect(ADDR) // Connect to brickd.
    defer ipcon.Disconnect()
    // Don't use device before ipcon is connected.

    // Get current color.
    r, g, b, c_, _ := c.GetColor()

    fmt.Printf("Color [R]: \n", r)
    fmt.Printf("Color [G]: \n", g)
    fmt.Printf("Color [B]: \n", b)
    fmt.Printf("Color [C]: \n", c_)

    fmt.Print("Press enter to exit.")
    fmt.Scanln()
}

Callback

Download (example_callback.go)

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
package main

import (
    "fmt"
    "github.com/Tinkerforge/go-api-bindings/color_bricklet"
    "github.com/Tinkerforge/go-api-bindings/ipconnection"
)

const ADDR string = "localhost:4223"
const UID string = "XYZ" // Change XYZ to the UID of your Color Bricklet.

func main() {
    ipcon := ipconnection.New()
    defer ipcon.Close()
    c, _ := color_bricklet.New(UID, &ipcon) // Create device object.

    ipcon.Connect(ADDR) // Connect to brickd.
    defer ipcon.Disconnect()
    // Don't use device before ipcon is connected.

    c.RegisterColorCallback(func(r uint16, g uint16, b uint16, c uint16) {
        fmt.Printf("Color [R]: %d\n", r)
        fmt.Printf("Color [G]: %d\n", g)
        fmt.Printf("Color [B]: %d\n", b)
        fmt.Printf("Color [C]: %d\n", c)
        fmt.Println()
    })

    // Set period for color receiver to 1s (1000ms).
    // Note: The color callback is only called every second
    //       if the color has changed since the last call!
    c.SetColorCallbackPeriod(1000)

    fmt.Print("Press enter to exit.")
    fmt.Scanln()
}

Threshold

Download (example_threshold.go)

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
package main

import (
    "fmt"
    "github.com/Tinkerforge/go-api-bindings/color_bricklet"
    "github.com/Tinkerforge/go-api-bindings/ipconnection"
)

const ADDR string = "localhost:4223"
const UID string = "XYZ" // Change XYZ to the UID of your Color Bricklet.

func main() {
    ipcon := ipconnection.New()
    defer ipcon.Close()
    c, _ := color_bricklet.New(UID, &ipcon) // Create device object.

    ipcon.Connect(ADDR) // Connect to brickd.
    defer ipcon.Disconnect()
    // Don't use device before ipcon is connected.

    // Get threshold receivers with a debounce time of 10 seconds (10000ms).
    c.SetDebouncePeriod(10000)

    c.RegisterColorReachedCallback(func(r uint16, g uint16, b uint16, c uint16) {
        fmt.Printf("Color [R]: %d\n", r)
        fmt.Printf("Color [G]: %d\n", g)
        fmt.Printf("Color [B]: %d\n", b)
        fmt.Printf("Color [C]: %d\n", c)
        fmt.Println()
    })

    // Configure threshold for color "greater than 100, 200, 300, 400".
    c.SetColorCallbackThreshold('>', 100, 0, 200, 0, 300, 0, 400, 0)

    fmt.Print("Press enter to exit.")
    fmt.Scanln()
}

API

The Color Bricklet's API is defined in the package github.com/Tinkerforge/go-api-bindings/color_bricklet

Nearly every function of the Go bindings can return an BrickletError, implementing the error interface. The error can have one of the following values:

  • BrickletErrorSuccess = 0
  • BrickletErrorInvalidParameter = 1
  • BrickletErrorFunctionNotSupported = 2
  • BrickletErrorUnknownError = 3

which correspond to the values returned from Bricks and Bricklets.

All functions listed below are thread-safe.

Basic Functions

func NewColorBricklet(uid string, ipcon *IPConnection)(device ColorBricklet, err error)

Creates a new ColorBricklet object with the unique device ID uid and adds it to the IPConnection ipcon:

This device object can be used after the IP connection has been connected (see examples above).

func (*ColorBricklet)GetColor()(r uint16, g uint16, b uint16, c uint16, err error)

Returns the measured color of the sensor. The values have a range of 0 to 65535.

The red (r), green (g), blue (b) and clear (c) colors are measured with four different photodiodes that are responsive at different wavelengths:

Chart Responsivity / Wavelength

If you want to get the color periodically, it is recommended to use the (*ColorBricklet) RegisterColorCallback callback and set the period with (*ColorBricklet) SetColorCallbackPeriod.

func (*ColorBricklet)LightOn()(err error)

Turns the LED on.

func (*ColorBricklet)LightOff()(err error)

Turns the LED off.

func (*ColorBricklet)IsLightOn()(light Light, err error)

Returns the state of the LED. Possible values are:

  • 0: On
  • 1: Off

The following constants are available for this function:

  • LightOn = 0
  • LightOff = 1
func (*ColorBricklet)SetConfig(gain Gain, integrationTime IntegrationTime)(err error)

Sets the configuration of the sensor. Gain and integration time can be configured in this way.

For configuring the gain:

  • 0: 1x Gain
  • 1: 4x Gain
  • 2: 16x Gain
  • 3: 60x Gain

For configuring the integration time:

  • 0: 2.4ms
  • 1: 24ms
  • 2: 101ms
  • 3: 154ms
  • 4: 700ms

Increasing the gain enables the sensor to detect a color from a higher distance.

The integration time provides a trade-off between conversion time and accuracy. With a longer integration time the values read will be more accurate but it will take longer time to get the conversion results.

The default values are 60x gain and 154ms integration time.

The following constants are available for this function:

  • Gain1x = 0
  • Gain4x = 1
  • Gain16x = 2
  • Gain60x = 3
  • IntegrationTime2ms = 0
  • IntegrationTime24ms = 1
  • IntegrationTime101ms = 2
  • IntegrationTime154ms = 3
  • IntegrationTime700ms = 4
func (*ColorBricklet)GetConfig()(gain Gain, integrationTime IntegrationTime, err error)

Returns the configuration as set by (*ColorBricklet) SetConfig.

The following constants are available for this function:

  • Gain1x = 0
  • Gain4x = 1
  • Gain16x = 2
  • Gain60x = 3
  • IntegrationTime2ms = 0
  • IntegrationTime24ms = 1
  • IntegrationTime101ms = 2
  • IntegrationTime154ms = 3
  • IntegrationTime700ms = 4
func (*ColorBricklet)GetIlluminance()(illuminance uint32, err error)

Returns the illuminance affected by the gain and integration time as set by (*ColorBricklet) SetConfig. To get the illuminance in Lux apply this formula:

lux = illuminance * 700 / gain / integration_time

To get a correct illuminance measurement make sure that the color values themself are not saturated. The color value (R, G or B) is saturated if it is equal to the maximum value of 65535. In that case you have to reduce the gain, see (*ColorBricklet) SetConfig.

func (*ColorBricklet)GetColorTemperature()(colorTemperature uint16, err error)

Returns the color temperature in Kelvin.

To get a correct color temperature measurement make sure that the color values themself are not saturated. The color value (R, G or B) is saturated if it is equal to the maximum value of 65535. In that case you have to reduce the gain, see (*ColorBricklet) SetConfig.

Advanced Functions

func (*ColorBricklet)GetAPIVersion()(apiVersion [3]uint8, err error)

Returns the version of the API definition (major, minor, revision) implemented by this API bindings. This is neither the release version of this API bindings nor does it tell you anything about the represented Brick or Bricklet.

func (*ColorBricklet)GetResponseExpected(functionId uint8)(responseExpected bool, err error)

Returns the response expected flag for the function specified by the function ID parameter. It is true if the function is expected to send a response, false otherwise.

For getter functions this is enabled by default and cannot be disabled, because those functions will always send a response. For callback configuration functions it is enabled by default too, but can be disabled by (*ColorBricklet) SetResponseExpected. For setter functions it is disabled by default and can be enabled.

Enabling the response expected flag for a setter function allows to detect timeouts and other error conditions calls of this setter as well. The device will then send a response for this purpose. If this flag is disabled for a setter function then no response is send and errors are silently ignored, because they cannot be detected.

See (*ColorBricklet) SetResponseExpected for the list of function ID constants available for this function.

func (*ColorBricklet)SetResponseExpected(functionId uint8, responseExpected bool)(err error)

Changes the response expected flag of the function specified by the function ID parameter. This flag can only be changed for setter (default value: false) and callback configuration functions (default value: true). For getter functions it is always enabled.

Enabling the response expected flag for a setter function allows to detect timeouts and other error conditions calls of this setter as well. The device will then send a response for this purpose. If this flag is disabled for a setter function then no response is send and errors are silently ignored, because they cannot be detected.

The following function ID constants are available for this function:

  • FunctionSetColorCallbackPeriod = 2
  • FunctionSetColorCallbackThreshold = 4
  • FunctionSetDebouncePeriod = 6
  • FunctionLightOn = 10
  • FunctionLightOff = 11
  • FunctionSetConfig = 13
  • FunctionSetIlluminanceCallbackPeriod = 17
  • FunctionSetColorTemperatureCallbackPeriod = 19
func (*ColorBricklet)SetResponseExpectedAll(responseExpected bool)(err error)

Changes the response expected flag for all setter and callback configuration functions of this device at once.

func (*ColorBricklet)GetIdentity()(uid string, connectedUid string, position rune, hardwareVersion [3]uint8, firmwareVersion [3]uint8, deviceIdentifier uint16, err error)

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' or 'd'.

The device identifier numbers can be found here. There is also a constant for the device identifier of this Bricklet.

Callback Configuration Functions

func (*ColorBricklet)SetColorCallbackPeriod(period uint32)(err error)

Sets the period in ms with which the (*ColorBricklet) RegisterColorCallback callback is triggered periodically. A value of 0 turns the callback off.

The (*ColorBricklet) RegisterColorCallback callback is only triggered if the color has changed since the last triggering.

The default value is 0.

func (*ColorBricklet)GetColorCallbackPeriod()(period uint32, err error)

Returns the period as set by (*ColorBricklet) SetColorCallbackPeriod.

func (*ColorBricklet)SetColorCallbackThreshold(option ThresholdOption, minR uint16, maxR uint16, minG uint16, maxG uint16, minB uint16, maxB uint16, minC uint16, maxC uint16)(err error)

Sets the thresholds for the (*ColorBricklet) RegisterColorReachedCallback callback.

The following options are possible:

Option Description
'x' Callback is turned off
'o' Callback is triggered when the temperature is outside the min and max values
'i' Callback is triggered when the temperature is inside the min and max values
'<' Callback is triggered when the temperature is smaller than the min value (max is ignored)
'>' Callback is triggered when the temperature is greater than the min value (max is ignored)

The default value is ('x', 0, 0, 0, 0, 0, 0, 0, 0).

The following constants are available for this function:

  • ThresholdOptionOff = 'x'
  • ThresholdOptionOutside = 'o'
  • ThresholdOptionInside = 'i'
  • ThresholdOptionSmaller = '<'
  • ThresholdOptionGreater = '>'
func (*ColorBricklet)GetColorCallbackThreshold()(option ThresholdOption, minR uint16, maxR uint16, minG uint16, maxG uint16, minB uint16, maxB uint16, minC uint16, maxC uint16, err error)

Returns the threshold as set by (*ColorBricklet) SetColorCallbackThreshold.

The following constants are available for this function:

  • ThresholdOptionOff = 'x'
  • ThresholdOptionOutside = 'o'
  • ThresholdOptionInside = 'i'
  • ThresholdOptionSmaller = '<'
  • ThresholdOptionGreater = '>'
func (*ColorBricklet)SetDebouncePeriod(debounce uint32)(err error)

Sets the period in ms with which the threshold callback

is triggered, if the threshold

keeps being reached.

The default value is 100.

func (*ColorBricklet)GetDebouncePeriod()(debounce uint32, err error)

Returns the debounce period as set by (*ColorBricklet) SetDebouncePeriod.

func (*ColorBricklet)SetIlluminanceCallbackPeriod(period uint32)(err error)

Sets the period in ms with which the (*ColorBricklet) RegisterIlluminanceCallback callback is triggered periodically. A value of 0 turns the callback off.

The (*ColorBricklet) RegisterIlluminanceCallback callback is only triggered if the illuminance has changed since the last triggering.

The default value is 0.

func (*ColorBricklet)GetIlluminanceCallbackPeriod()(period uint32, err error)

Returns the period as set by (*ColorBricklet) SetIlluminanceCallbackPeriod.

func (*ColorBricklet)SetColorTemperatureCallbackPeriod(period uint32)(err error)

Sets the period in ms with which the (*ColorBricklet) RegisterColorTemperatureCallback callback is triggered periodically. A value of 0 turns the callback off.

The (*ColorBricklet) RegisterColorTemperatureCallback callback is only triggered if the color temperature has changed since the last triggering.

The default value is 0.

func (*ColorBricklet)GetColorTemperatureCallbackPeriod()(period uint32, err error)

Returns the period as set by (*ColorBricklet) SetColorTemperatureCallbackPeriod.

Callbacks

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done with the corresponding Register*Callback function, which returns a unique callback ID. This ID can be used to deregister the callback later.

Note

Using callbacks for recurring events is always preferred compared to using getters. It will use less USB bandwidth and the latency will be a lot better, since there is no round trip time.

func (*ColorBricklet)RegisterColorCallback(func(r uint16, g uint16, b uint16, c uint16))(callbackID uint64)

A callback can be registered for this event with the RegisterColorCallback() function. This function returns the ID of the registered callback. An added callback can be removed with the DeregisterColorCallback(callbackID uint64) function.

This callback is triggered periodically with the period that is set by (*ColorBricklet) SetColorCallbackPeriod. The callback parameter is the color of the sensor as RGBC.

The (*ColorBricklet) RegisterColorCallback callback is only triggered if the color has changed since the last triggering.

func (*ColorBricklet)RegisterColorReachedCallback(func(r uint16, g uint16, b uint16, c uint16))(callbackID uint64)

A callback can be registered for this event with the RegisterColorReachedCallback() function. This function returns the ID of the registered callback. An added callback can be removed with the DeregisterColorReachedCallback(callbackID uint64) function.

This callback is triggered when the threshold as set by (*ColorBricklet) SetColorCallbackThreshold is reached. The callback parameter is the color of the sensor as RGBC.

If the threshold keeps being reached, the callback is triggered periodically with the period as set by (*ColorBricklet) SetDebouncePeriod.

func (*ColorBricklet)RegisterIlluminanceCallback(func(illuminance uint32))(callbackID uint64)

A callback can be registered for this event with the RegisterIlluminanceCallback() function. This function returns the ID of the registered callback. An added callback can be removed with the DeregisterIlluminanceCallback(callbackID uint64) function.

This callback is triggered periodically with the period that is set by (*ColorBricklet) SetIlluminanceCallbackPeriod. The callback parameter is the illuminance. See (*ColorBricklet) GetIlluminance for how to interpret this value.

The (*ColorBricklet) RegisterIlluminanceCallback callback is only triggered if the illuminance has changed since the last triggering.

func (*ColorBricklet)RegisterColorTemperatureCallback(func(colorTemperature uint16))(callbackID uint64)

A callback can be registered for this event with the RegisterColorTemperatureCallback() function. This function returns the ID of the registered callback. An added callback can be removed with the DeregisterColorTemperatureCallback(callbackID uint64) function.

This callback is triggered periodically with the period that is set by (*ColorBricklet) SetColorTemperatureCallbackPeriod. The callback parameter is the color temperature in Kelvin.

The (*ColorBricklet) RegisterColorTemperatureCallback callback is only triggered if the color temperature has changed since the last triggering.

Constants

color_bricklet.DeviceIdentifier

This constant is used to identify a Color Bricklet.

The (*ColorBricklet) GetIdentity function and the (*IPConnection) RegisterEnumerateCallback callback of the IP Connection have a deviceIdentifier parameter to specify the Brick's or Bricklet's type.

color_bricklet.DeviceDisplayName

This constant represents the human readable name of a Color Bricklet.