Merge pull request #478 from conejoninja/bh1750-light-sensor

Added basic driver for BH1750 (light sensor), board GY-302

drivers/i2c/README.md

@@ -15,6 +15,7 @@ Gobot has a extensible system for connecting to hardware devices. The following
 - Adafruit Motor Hat
 - ADS1015 Analog to Digital Converter
 - ADS1115 Analog to Digital Converter
+- BH1750 Digital Luminosity/Lux/Light Sensor
 - BlinkM LED
 - BME280 Barometric Pressure/Temperature/Altitude/Humidity Sensor
 - BMP180 Barometric Pressure/Temperature/Altitude Sensor

drivers/i2c/bh1750_driver.go

@@ -0,0 +1,113 @@
+package i2c
+
+import (
+	"time"
+	"errors"
+
+	"gobot.io/x/gobot"
+)
+
+const bh1750Address = 0x23
+
+const (
+	BH1750_POWER_DOWN                 = 0x00
+	BH1750_POWER_ON                   = 0x01
+	BH1750_RESET                      = 0x07
+	BH1750_CONTINUOUS_HIGH_RES_MODE   = 0x10
+	BH1750_CONTINUOUS_HIGH_RES_MODE_2 = 0x11
+	BH1750_CONTINUOUS_LOW_RES_MODE    = 0x13
+	BH1750_ONE_TIME_HIGH_RES_MODE     = 0x20
+	BH1750_ONE_TIME_HIGH_RES_MODE_2   = 0x21
+	BH1750_ONE_TIME_LOW_RES_MODE      = 0x23
+)
+
+// BH1750Driver is a driver for the BH1750 digital Ambient Light Sensor IC for I²C bus interface.
+//
+type BH1750Driver struct {
+	name       string
+	connector  Connector
+	connection Connection
+	mode       byte
+	Config
+}
+
+// NewBH1750Driver creates a new driver with specified i2c interface
+// Params:
+//		conn Connector - the Adaptor to use with this Driver
+//
+// Optional params:
+//		i2c.WithBus(int):	bus to use with this driver
+//		i2c.WithAddress(int):	address to use with this driver
+//
+func NewBH1750Driver(a Connector, options ...func(Config)) *BH1750Driver {
+	m := &BH1750Driver{
+		name:      gobot.DefaultName("BH1750"),
+		connector: a,
+		Config:    NewConfig(),
+		mode: BH1750_CONTINUOUS_HIGH_RES_MODE,
+	}
+
+	for _, option := range options {
+		option(m)
+	}
+
+	// TODO: add commands for API
+	return m
+}
+
+// Name returns the Name for the Driver
+func (h *BH1750Driver) Name() string { return h.name }
+
+// SetName sets the Name for the Driver
+func (h *BH1750Driver) SetName(n string) { h.name = n }
+
+// Connection returns the connection for the Driver
+func (h *BH1750Driver) Connection() gobot.Connection { return h.connector.(gobot.Connection) }
+
+// Start initialized the bh1750
+func (h *BH1750Driver) Start() (err error) {
+	bus := h.GetBusOrDefault(h.connector.GetDefaultBus())
+	address := h.GetAddressOrDefault(bh1750Address)
+
+	h.connection, err = h.connector.GetConnection(address, bus)
+	if err != nil {
+		return err
+	}
+
+	err = h.connection.WriteByte(h.mode)
+	time.Sleep(10 * time.Microsecond)
+	if err != nil {
+		return err
+	}
+
+	return
+}
+
+// Halt returns true if devices is halted successfully
+func (h *BH1750Driver) Halt() (err error) { return }
+
+// RawSensorData returns the raw value from the bh1750
+func (h *BH1750Driver) RawSensorData() (level int, err error) {
+
+	buf := []byte{0, 0}
+	bytesRead, err := h.connection.Read(buf)
+	if bytesRead != 2 {
+		err = errors.New("wrong number of bytes read")
+		return
+	}
+	if err != nil {
+		return
+	}
+	level = int(buf[0])<<8 | int(buf[1])
+
+	return
+}
+
+// Lux returns the adjusted value from the bh1750
+func (h *BH1750Driver) Lux() (lux int, err error) {
+
+	lux, err = h.RawSensorData()
+	lux = int(float64(lux) / 1.2)
+
+	return
+}

drivers/i2c/bh1750_driver_test.go

@@ -0,0 +1,148 @@
+package i2c
+
+import (
+	"errors"
+	"strings"
+	"testing"
+
+	"bytes"
+
+	"gobot.io/x/gobot"
+	"gobot.io/x/gobot/gobottest"
+)
+
+var _ gobot.Driver = (*BH1750Driver)(nil)
+
+// --------- HELPERS
+func initTestBH1750Driver() (driver *BH1750Driver) {
+	driver, _ = initTestBH1750DriverWithStubbedAdaptor()
+	return
+}
+
+func initTestBH1750DriverWithStubbedAdaptor() (*BH1750Driver, *i2cTestAdaptor) {
+	adaptor := newI2cTestAdaptor()
+	return NewBH1750Driver(adaptor), adaptor
+}
+
+// --------- TESTS
+
+func TestNewBH1750Driver(t *testing.T) {
+	// Does it return a pointer to an instance of BH1750Driver?
+	var mma interface{} = NewBH1750Driver(newI2cTestAdaptor())
+	_, ok := mma.(*BH1750Driver)
+	if !ok {
+		t.Errorf("NewBH1750Driver() should have returned a *BH1750Driver")
+	}
+}
+
+// Methods
+func TestBH1750Driver(t *testing.T) {
+	mma := initTestBH1750Driver()
+
+	gobottest.Refute(t, mma.Connection(), nil)
+	gobottest.Assert(t, strings.HasPrefix(mma.Name(), "BH1750"), true)
+}
+
+func TestBH1750DriverSetName(t *testing.T) {
+	d := initTestBH1750Driver()
+	d.SetName("TESTME")
+	gobottest.Assert(t, d.Name(), "TESTME")
+}
+
+func TestBH1750DriverOptions(t *testing.T) {
+	d := NewBH1750Driver(newI2cTestAdaptor(), WithBus(2))
+	gobottest.Assert(t, d.GetBusOrDefault(1), 2)
+}
+
+func TestBH1750DriverStart(t *testing.T) {
+	d := initTestBH1750Driver()
+	gobottest.Assert(t, d.Start(), nil)
+}
+
+func TestBH1750StartConnectError(t *testing.T) {
+	d, adaptor := initTestBH1750DriverWithStubbedAdaptor()
+	adaptor.Testi2cConnectErr(true)
+	gobottest.Assert(t, d.Start(), errors.New("Invalid i2c connection"))
+}
+
+func TestBH1750DriverStartWriteError(t *testing.T) {
+	mma, adaptor := initTestBH1750DriverWithStubbedAdaptor()
+	adaptor.i2cWriteImpl = func([]byte) (int, error) {
+		return 0, errors.New("write error")
+	}
+	gobottest.Assert(t, mma.Start(), errors.New("write error"))
+}
+
+func TestBH1750DriverHalt(t *testing.T) {
+	d := initTestBH1750Driver()
+	gobottest.Assert(t, d.Halt(), nil)
+}
+
+func TestBH1750DriverNullLux(t *testing.T) {
+	d, _ := initTestBH1750DriverWithStubbedAdaptor()
+	d.Start()
+	lux, _ := d.Lux()
+	gobottest.Assert(t, lux, 0)
+}
+
+func TestBH1750DriverLux(t *testing.T) {
+	d, adaptor := initTestBH1750DriverWithStubbedAdaptor()
+	d.Start()
+
+	adaptor.i2cReadImpl = func(b []byte) (int, error) {
+		buf := new(bytes.Buffer)
+		buf.Write([]byte{0x05, 0xb0})
+		copy(b, buf.Bytes())
+		return buf.Len(), nil
+	}
+
+	lux, _ := d.Lux()
+	gobottest.Assert(t, lux, 1213)
+}
+
+func TestBH1750DriverNullRawSensorData(t *testing.T) {
+	d, _ := initTestBH1750DriverWithStubbedAdaptor()
+	d.Start()
+	level, _ := d.RawSensorData()
+	gobottest.Assert(t, level, 0)
+}
+
+func TestBH1750DriverRawSensorData(t *testing.T) {
+	d, adaptor := initTestBH1750DriverWithStubbedAdaptor()
+	d.Start()
+
+	adaptor.i2cReadImpl = func(b []byte) (int, error) {
+		buf := new(bytes.Buffer)
+		buf.Write([]byte{0x05, 0xb0})
+		copy(b, buf.Bytes())
+		return buf.Len(), nil
+	}
+
+	level, _ := d.RawSensorData()
+	gobottest.Assert(t, level, 1456)
+}
+
+func TestBH1750DriverLuxError(t *testing.T) {
+	d, adaptor := initTestBH1750DriverWithStubbedAdaptor()
+	d.Start()
+
+	adaptor.i2cReadImpl = func(b []byte) (int, error) {
+		return 0, errors.New("wrong number of bytes read")
+	}
+
+	_, err := d.Lux()
+	gobottest.Assert(t, err, errors.New("wrong number of bytes read"))
+}
+
+func TestBH1750DriverRawSensorDataError(t *testing.T) {
+	d, adaptor := initTestBH1750DriverWithStubbedAdaptor()
+	d.Start()
+
+	adaptor.i2cReadImpl = func(b []byte) (int, error) {
+		return 0, errors.New("wrong number of bytes read")
+	}
+
+	_, err := d.RawSensorData()
+	gobottest.Assert(t, err, errors.New("wrong number of bytes read"))
+}
+