Class: IoT::MAX44009

Inherits:
Object
  • Object
show all
Defined in:
lib/iot/max44009.rb

Overview

MAX44009 - low-power ambient Light Sensor Output: digital, Bus: I²C, Range: 0.045..188,000 Lux, VCC: 1.7..3.6V, Operating Current: 0.65µA datasheets.maximintegrated.com/en/ds/MAX44009.pdf

Constant Summary collapse

MAX44009_DEFAULT_ADDRESS = 
0x4A
MAX44009_REG_INTR_STATUS =

MAX44009 Register Map

0x00
MAX44009_REG_INTR_ENABLE =

Interrupt Status Register

0x01
MAX44009_REG_CONFIG =

Interrupt Enable Register

0x02
MAX44009_REG_LUX_HIGH =

Configuration Register

0x03
MAX44009_REG_LUX_LOW =

Lux High Byte

0x04
MAX44009_REG_THRES_UP_HI =

Lux Low Byte

0x05
MAX44009_REG_THRES_LO_HI =

Upper Threshold High Byte

0x06
MAX44009_REG_THRES_TIMER =

Upper Threshold Low Byte

0x07
MAX44009_REG_INTR_ENABLE_NO_ASSRT =

MAX44009 INTERRUPT ENABLE REGISTER

0x00
MAX44009_REG_INTR_ENABLE_TRIGGER =

The INT pin and the INTS bit are not asserted even if an interrupt event has occurred

0x01
MAX44009_REG_CONFIG_CONTMODE_DEFAULT =

MAX44009 CONFIGURATION REGISTER

0x00
MAX44009_REG_CONFIG_CONTMODE_CONTIN =

Default mode

0x80
MAX44009_REG_CONFIG_MANUAL_DEFAULT =

Continuous mode

0x00
MAX44009_REG_CONFIG_MANUAL_MODEON =

Default mode of configuration is used for the IC

0x40
MAX44009_REG_CONFIG_CDR_NODIVIDED =

Manual mode of configuration is used for the IC

0x00
MAX44009_REG_CONFIG_CDR_DIVIDED =

Current not divided. All of the photodiode current goes to the ADC

0x08
MAX44009_REG_CONFIG_INTRTIMER_800 =

Current divided by 8

0x00
MAX44009_REG_CONFIG_INTRTIMER_400 =

Integration Time = 800ms, This is a preferred mode for boosting low-light sensitivity

0x01
MAX44009_REG_CONFIG_INTRTIMER_200 =

Integration Time = 400ms

0x02
MAX44009_REG_CONFIG_INTRTIMER_100 =

Integration Time = 200ms

0x03
MAX44009_REG_CONFIG_INTRTIMER_50 =

Integration Time = 100ms, This is a preferred mode for high-brightness applications

0x04
MAX44009_REG_CONFIG_INTRTIMER_25 =

Integration Time = 50ms, Manual Mode only

0x05
MAX44009_REG_CONFIG_INTRTIMER_12_5 =

Integration Time = 25ms, Manual Mode only

0x06
MAX44009_REG_CONFIG_INTRTIMER_6_25 =

Integration Time = 12.5ms, Manual Mode only

0x07
DEVICE =

Integration Time = 6.25ms, Manual Mode only

MAX44009_DEFAULT_ADDRESS

Instance Method Summary collapse

Constructor Details

#initialize(i2c_bus = '/dev/i2c-1') ⇒ MAX44009

I2C sensor address



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# File 'lib/iot/max44009.rb', line 39

def initialize(i2c_bus='/dev/i2c-1')
  @sensor_name = 'MAX44009'
  @i2c_bus = i2c_bus
  @device = I2CDevice.new(address: DEVICE, driver: I2CDevice::Driver::I2CDev.new(@i2c_bus))
  write_config()
  @length = 2
  @value = read_sensor
end

Instance Method Details

#lux ⇒ Object 



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# File 'lib/iot/max44009.rb', line 64

def lux
# Return value in LX
  read_sensor
  @value
end

#name ⇒ Object 



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# File 'lib/iot/max44009.rb', line 48

def name
  @sensor_name
end

#read_sensor ⇒ Object 



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# File 'lib/iot/max44009.rb', line 58

def read_sensor
  # Read data back from MAX44009_REG_LUX_HIGH(0x03), 2 bytes, luminance MSB, luminance LSB
  data = @device.i2cget(MAX44009_REG_LUX_HIGH, 2)
  @value = data_to_lux(data)
end

#write_config ⇒ Object 



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# File 'lib/iot/max44009.rb', line 52

def write_config()
  # Select the configuration register data from the given provided values
  config = (MAX44009_REG_CONFIG_CONTMODE_CONTIN | MAX44009_REG_CONFIG_MANUAL_MODEON | MAX44009_REG_CONFIG_CDR_NODIVIDED | MAX44009_REG_CONFIG_INTRTIMER_800)
  @device.i2cset(MAX44009_REG_CONFIG, config)
end