Go - Accelerometer Bricklet

This is the description of the Go API bindings for the Accelerometer Bricklet. General information and technical specifications for the Accelerometer 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)

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package main

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

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

func main() {
    ipcon := ipconnection.New()
    defer ipcon.Close()
    a, _ := accelerometer_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 acceleration.
    x, y, z, _ := a.GetAcceleration()

    fmt.Printf("Acceleration [X]: %f g\n", float64(x)/1000.0)
    fmt.Printf("Acceleration [Y]: %f g\n", float64(y)/1000.0)
    fmt.Printf("Acceleration [Z]: %f g\n", float64(z)/1000.0)

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

Callback

Download (example_callback.go)

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package main

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

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

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

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

    a.RegisterAccelerationCallback(func(x int16, y int16, z int16) {
        fmt.Printf("Acceleration [X]: %f g\n", float64(x)/1000.0)
        fmt.Printf("Acceleration [Y]: %f g\n", float64(y)/1000.0)
        fmt.Printf("Acceleration [Z]: %f g\n", float64(z)/1000.0)
        fmt.Println()
    })

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

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

Threshold

Download (example_threshold.go)

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package main

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

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

func main() {
    ipcon := ipconnection.New()
    defer ipcon.Close()
    a, _ := accelerometer_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).
    a.SetDebouncePeriod(10000)

    a.RegisterAccelerationReachedCallback(func(x int16, y int16, z int16) {
        fmt.Printf("Acceleration [X]: %f g\n", float64(x)/1000.0)
        fmt.Printf("Acceleration [Y]: %f g\n", float64(y)/1000.0)
        fmt.Printf("Acceleration [Z]: %f g\n", float64(z)/1000.0)
        fmt.Println()
    })

    // Configure threshold for acceleration "greater than 2 g, 2 g, 2 g".
    a.SetAccelerationCallbackThreshold('>', 2*1000, 0, 2*1000, 0, 2*1000, 0)

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

API

The Accelerometer Bricklet API is defined in the package github.com/Tinkerforge/go-api-bindings/accelerometer_bricklet

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

  • DeviceErrorSuccess = 0
  • DeviceErrorInvalidParameter = 1
  • DeviceErrorFunctionNotSupported = 2
  • DeviceErrorUnknownError = 3

which correspond to the values returned from Bricks and Bricklets.

All functions listed below are thread-safe.

Basic Functions

func NewAccelerometerBricklet(uid string, ipcon *IPConnection) (device AccelerometerBricklet, err error)

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

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

func (*AccelerometerBricklet) GetAcceleration() (x int16, y int16, z int16, err error)

Returns the acceleration in x, y and z direction. The values are given in g/1000 (1g = 9.80665m/s²), not to be confused with grams.

If you want to get the acceleration periodically, it is recommended to use the RegisterAccelerationCallback callback and set the period with SetAccelerationCallbackPeriod().

func (*AccelerometerBricklet) GetTemperature() (temperature int16, err error)

Returns the temperature of the accelerometer in °C.

func (*AccelerometerBricklet) LEDOn() (err error)

Enables the LED on the Bricklet.

func (*AccelerometerBricklet) LEDOff() (err error)

Disables the LED on the Bricklet.

func (*AccelerometerBricklet) IsLEDOn() (on bool, err error)

Returns true if the LED is enabled, false otherwise.

Advanced Functions

func (*AccelerometerBricklet) SetConfiguration(dataRate DataRate, fullScale FullScale, filterBandwidth FilterBandwidth) (err error)

Configures the data rate, full scale range and filter bandwidth. Possible values are:

  • Data rate of 0Hz to 1600Hz.
  • Full scale range of -2G to +2G up to -16G to +16G.
  • Filter bandwidth between 50Hz and 800Hz.

Decreasing data rate or full scale range will also decrease the noise on the data.

The default values are 100Hz data rate, -4G to +4G range and 200Hz filter bandwidth.

The following constants are available for this function:

  • DataRateOff = 0
  • DataRate3Hz = 1
  • DataRate6Hz = 2
  • DataRate12Hz = 3
  • DataRate25Hz = 4
  • DataRate50Hz = 5
  • DataRate100Hz = 6
  • DataRate400Hz = 7
  • DataRate800Hz = 8
  • DataRate1600Hz = 9
  • FullScale2g = 0
  • FullScale4g = 1
  • FullScale6g = 2
  • FullScale8g = 3
  • FullScale16g = 4
  • FilterBandwidth800Hz = 0
  • FilterBandwidth400Hz = 1
  • FilterBandwidth200Hz = 2
  • FilterBandwidth50Hz = 3
func (*AccelerometerBricklet) GetConfiguration() (dataRate DataRate, fullScale FullScale, filterBandwidth FilterBandwidth, err error)

Returns the configuration as set by SetConfiguration().

The following constants are available for this function:

  • DataRateOff = 0
  • DataRate3Hz = 1
  • DataRate6Hz = 2
  • DataRate12Hz = 3
  • DataRate25Hz = 4
  • DataRate50Hz = 5
  • DataRate100Hz = 6
  • DataRate400Hz = 7
  • DataRate800Hz = 8
  • DataRate1600Hz = 9
  • FullScale2g = 0
  • FullScale4g = 1
  • FullScale6g = 2
  • FullScale8g = 3
  • FullScale16g = 4
  • FilterBandwidth800Hz = 0
  • FilterBandwidth400Hz = 1
  • FilterBandwidth200Hz = 2
  • FilterBandwidth50Hz = 3
func (*AccelerometerBricklet) 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 (*AccelerometerBricklet) 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 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 SetResponseExpected() for the list of function ID constants available for this function.

func (*AccelerometerBricklet) 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:

  • FunctionSetAccelerationCallbackPeriod = 2
  • FunctionSetAccelerationCallbackThreshold = 4
  • FunctionSetDebouncePeriod = 6
  • FunctionSetConfiguration = 9
  • FunctionLEDOn = 11
  • FunctionLEDOff = 12
func (*AccelerometerBricklet) SetResponseExpectedAll(responseExpected bool) (err error)

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

func (*AccelerometerBricklet) 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 (*AccelerometerBricklet) SetAccelerationCallbackPeriod(period uint32) (err error)

Sets the period in ms with which the RegisterAccelerationCallback callback is triggered periodically. A value of 0 turns the callback off.

The RegisterAccelerationCallback callback is only triggered if the acceleration has changed since the last triggering.

The default value is 0.

func (*AccelerometerBricklet) GetAccelerationCallbackPeriod() (period uint32, err error)

Returns the period as set by SetAccelerationCallbackPeriod().

func (*AccelerometerBricklet) SetAccelerationCallbackThreshold(option ThresholdOption, minX int16, maxX int16, minY int16, maxY int16, minZ int16, maxZ int16) (err error)

Sets the thresholds for the RegisterAccelerationReachedCallback callback.

The following options are possible:

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

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

The following constants are available for this function:

  • ThresholdOptionOff = 'x'
  • ThresholdOptionOutside = 'o'
  • ThresholdOptionInside = 'i'
  • ThresholdOptionSmaller = '<'
  • ThresholdOptionGreater = '>'
func (*AccelerometerBricklet) GetAccelerationCallbackThreshold() (option ThresholdOption, minX int16, maxX int16, minY int16, maxY int16, minZ int16, maxZ int16, err error)

Returns the threshold as set by SetAccelerationCallbackThreshold().

The following constants are available for this function:

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

Returns the debounce period as set by SetDebouncePeriod().

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 (*AccelerometerBricklet) RegisterAccelerationCallback(func(x int16, y int16, z int16)) (registrationId uint64)

A callback can be registered for this event with the RegisterAccelerationCallback() function. This function returns the ID of the registered callback. An added callback can be removed with the DeregisterAccelerationCallback(registrationId uint64) function.

This callback is triggered periodically with the period that is set by SetAccelerationCallbackPeriod(). The callback parameters are the X, Y and Z acceleration.

The RegisterAccelerationCallback callback is only triggered if the acceleration has changed since the last triggering.

func (*AccelerometerBricklet) RegisterAccelerationReachedCallback(func(x int16, y int16, z int16)) (registrationId uint64)

A callback can be registered for this event with the RegisterAccelerationReachedCallback() function. This function returns the ID of the registered callback. An added callback can be removed with the DeregisterAccelerationReachedCallback(registrationId uint64) function.

This callback is triggered when the threshold as set by SetAccelerationCallbackThreshold() is reached. The callback parameters are the X, Y and Z acceleration.

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

Constants

accelerometer_bricklet.DeviceIdentifier

This constant is used to identify a Accelerometer Bricklet.

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

accelerometer_bricklet.DeviceDisplayName

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