94 lines
2.1 KiB
Go
94 lines
2.1 KiB
Go
package microbit
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import (
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"bytes"
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"encoding/binary"
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"gobot.io/x/gobot"
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"gobot.io/x/gobot/platforms/ble"
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)
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// MagnetometerDriver is the Gobot driver for the Microbit's built-in magnetometer
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type MagnetometerDriver struct {
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name string
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connection gobot.Connection
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gobot.Eventer
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}
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type RawMagnetometerData 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 MagnetometerData struct {
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X float32
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Y float32
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Z float32
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}
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const (
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// BLE services
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magnetometerService = "e95df2d8251d470aa062fa1922dfa9a8"
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// BLE characteristics
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magnetometerCharacteristic = "e95dfb11251d470aa062fa1922dfa9a8"
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// Magnetometer event
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Magnetometer = "magnetometer"
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)
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// NewMagnetometerDriver creates a Microbit MagnetometerDriver
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func NewMagnetometerDriver(a ble.BLEConnector) *MagnetometerDriver {
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n := &MagnetometerDriver{
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name: gobot.DefaultName("Microbit Magnetometer"),
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connection: a,
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Eventer: gobot.NewEventer(),
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}
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n.AddEvent(Magnetometer)
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return n
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}
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// Connection returns the BLE connection
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func (b *MagnetometerDriver) Connection() gobot.Connection { return b.connection }
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// Name returns the Driver Name
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func (b *MagnetometerDriver) Name() string { return b.name }
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// SetName sets the Driver Name
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func (b *MagnetometerDriver) SetName(n string) { b.name = n }
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// adaptor returns BLE adaptor
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func (b *MagnetometerDriver) adaptor() ble.BLEConnector {
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return b.Connection().(ble.BLEConnector)
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}
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// Start tells driver to get ready to do work
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func (b *MagnetometerDriver) Start() (err error) {
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// subscribe to magnetometer notifications
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b.adaptor().Subscribe(magnetometerCharacteristic, func(data []byte, e error) {
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a := &RawMagnetometerData{X: 0, Y: 0, Z: 0}
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buf := bytes.NewBuffer(data)
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binary.Read(buf, binary.LittleEndian, &a.X)
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binary.Read(buf, binary.LittleEndian, &a.Y)
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binary.Read(buf, binary.LittleEndian, &a.Z)
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result := &MagnetometerData{
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X: float32(a.X) / 1000.0,
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Y: float32(a.Y) / 1000.0,
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Z: float32(a.Z) / 1000.0}
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b.Publish(b.Event(Magnetometer), result)
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})
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return
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}
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// Halt stops LED driver (void)
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func (b *MagnetometerDriver) Halt() (err error) {
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return
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}
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