147 lines
3.6 KiB
Go
147 lines
3.6 KiB
Go
package i2c
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import (
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"bytes"
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"encoding/binary"
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"time"
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"github.com/hybridgroup/gobot"
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)
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var _ gobot.Driver = (*MPU6050Driver)(nil)
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const mpu6050Address = 0x68
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const MPU6050_RA_ACCEL_XOUT_H = 0x3B
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const MPU6050_RA_PWR_MGMT_1 = 0x6B
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const MPU6050_PWR1_CLKSEL_BIT = 2
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const MPU6050_PWR1_CLKSEL_LENGTH = 3
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const MPU6050_CLOCK_PLL_XGYRO = 0x01
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const MPU6050_GYRO_FS_250 = 0x00
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const MPU6050_RA_GYRO_CONFIG = 0x1B
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const MPU6050_GCONFIG_FS_SEL_LENGTH = 2
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const MPU6050_GCONFIG_FS_SEL_BIT = 4
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const MPU6050_RA_ACCEL_CONFIG = 0x1C
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const MPU6050_ACONFIG_AFS_SEL_BIT = 4
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const MPU6050_ACONFIG_AFS_SEL_LENGTH = 2
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const MPU6050_ACCEL_FS_2 = 0x00
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const MPU6050_PWR1_SLEEP_BIT = 6
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const MPU6050_PWR1_ENABLE_BIT = 0
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type ThreeDData struct {
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X int16
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Y int16
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Z int16
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}
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type MPU6050Driver struct {
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name string
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connection I2c
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interval time.Duration
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Accelerometer ThreeDData
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Gyroscope ThreeDData
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Temperature int16
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gobot.Eventer
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}
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// NewMPU6050Driver creates a new driver with specified name and i2c interface
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func NewMPU6050Driver(a I2c, name string, v ...time.Duration) *MPU6050Driver {
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m := &MPU6050Driver{
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name: name,
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connection: a,
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interval: 10 * time.Millisecond,
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Eventer: gobot.NewEventer(),
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}
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if len(v) > 0 {
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m.interval = v[0]
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}
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m.AddEvent(Error)
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return m
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}
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func (h *MPU6050Driver) Name() string { return h.name }
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func (h *MPU6050Driver) Connection() gobot.Connection { return h.connection.(gobot.Connection) }
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// Start writes initialization bytes and reads from adaptor
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// using specified interval to accelerometer andtemperature data
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func (h *MPU6050Driver) Start() (errs []error) {
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if err := h.initialize(); err != nil {
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return []error{err}
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}
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go func() {
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for {
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if err := h.connection.I2cWrite(mpu6050Address, []byte{MPU6050_RA_ACCEL_XOUT_H}); err != nil {
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gobot.Publish(h.Event(Error), err)
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continue
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}
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ret, err := h.connection.I2cRead(mpu6050Address, 14)
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if err != nil {
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gobot.Publish(h.Event(Error), err)
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continue
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}
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buf := bytes.NewBuffer(ret)
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binary.Read(buf, binary.BigEndian, &h.Accelerometer)
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binary.Read(buf, binary.BigEndian, &h.Temperature)
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binary.Read(buf, binary.BigEndian, &h.Gyroscope)
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h.convertToCelsius()
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<-time.After(h.interval)
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}
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}()
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return
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}
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// Halt returns true if devices is halted successfully
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func (h *MPU6050Driver) Halt() (errs []error) { return }
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func (h *MPU6050Driver) initialize() (err error) {
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if err = h.connection.I2cStart(mpu6050Address); err != nil {
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return
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}
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// setClockSource
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if err = h.connection.I2cWrite(mpu6050Address, []byte{MPU6050_RA_PWR_MGMT_1,
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MPU6050_PWR1_CLKSEL_BIT,
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MPU6050_PWR1_CLKSEL_LENGTH,
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MPU6050_CLOCK_PLL_XGYRO}); err != nil {
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return
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}
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// setFullScaleGyroRange
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if err = h.connection.I2cWrite(mpu6050Address, []byte{MPU6050_RA_GYRO_CONFIG,
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MPU6050_GCONFIG_FS_SEL_BIT,
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MPU6050_GCONFIG_FS_SEL_LENGTH,
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MPU6050_GYRO_FS_250}); err != nil {
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return
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}
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// setFullScaleAccelRange
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if err = h.connection.I2cWrite(mpu6050Address, []byte{MPU6050_RA_ACCEL_CONFIG,
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MPU6050_ACONFIG_AFS_SEL_BIT,
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MPU6050_ACONFIG_AFS_SEL_LENGTH,
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MPU6050_ACCEL_FS_2}); err != nil {
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return
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}
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// setSleepEnabled
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if err = h.connection.I2cWrite(mpu6050Address, []byte{MPU6050_RA_PWR_MGMT_1,
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MPU6050_PWR1_ENABLE_BIT,
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0}); err != nil {
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return
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}
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return nil
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}
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// The temperature sensor is -40 to +85 degrees Celsius.
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// It is a signed integer.
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// According to the datasheet:
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// 340 per degrees Celsius, -512 at 35 degrees.
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// At 0 degrees: -512 - (340 * 35) = -12412
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func (h *MPU6050Driver) convertToCelsius() {
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h.Temperature = (h.Temperature + 12412) / 340
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}
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