Implement TSL2561 module

[Aeprox]

I've adapted some existing C code for interfacing with the tsl2561 light sensor chips over I2C. There's already a lua module for the device in the repo, but I figured this would have better performance and memory savings.

Any feedback is much appreciated.

tsl2561 module

• tsl2561.init()
• tsl2561.settiming()
• tsl2561.getlux()
• tsl2561.getrawchannels()

tsl2561.init()

Description

Initializes the device on pins sdapin&sclpin. Optionally also configures the devices address and package. (Default: address pin floating (0x39) and FN package)

Syntax

tsl2561.init(sdapin, sclpin)
tsl2561.init(sdapin, sclpin, address)
tsl2561.init(sdapin, sclpin, address, package)

Parameters

• sdapin: Pin number of the device's I2C sda connection
• sclpin: Pin number of the device's I2C scl connection
• (optional) address: Address of the device on the I2C bus
  • tsl2561.ADDRESS_GND
  • tsl2561.ADDRESS_FLOAT (default)
  • tsl2561.ADDRESS_VDD
• (optional) package: Device's package type (slight difference in lux calculation)
  • tsl2561.PACKAGE_CS
  • tsl2561.PACKAGE_T_FN_CL (default)

Return

status: value indicating success or failure as explained below

• 0: tsl2561.TSL2561_OK
• 1: tsl2561.TSL2561_ERROR_I2CINIT: Can't initialize I2C bus
• 2: tsl2561.TSL2561_ERROR_I2CBUSY: I2C bus busy
• 3: tsl2561.TSL2561_ERROR_NOINIT: Initialize I2C bus before calling function
• 4: tsl2561.TSL2561_ERROR_LAST

Example

status = tsl2561.init(5,6,tsl2561.ADDRESS_FLOAT, tsl2561.PACKAGE_T_FN_CL)
if (status == 0) then
  lux = tsl2561.getlux()
  print("Illuminance: "..lux.." lx") 
end

tsl2561.settiming()

Description

Sets the integration time and gain settings of the device. When init() is called, these values default to 402ms and no gain.

Syntax

tsl2561.settiming(integration, gain)

Parameters

• integration: Sets the device's integration period. Valid options:
  • tsl2561.INTEGRATIONTIME_13MS
  • tsl2561.INTEGRATIONTIME_101MS
  • tsl2561.INTEGRATIONTIME_402MS (default)
• gain: Sets the device's gain. Valid options:
  • tsl2561.GAIN_1X (default)
  • tsl2561.GAIN_16X

Return

status: value indicating success or failure as explained below

• 0: tsl2561.TSL2561_OK
• 1: tsl2561.TSL2561_ERROR_I2CINIT: Can't initialize I2C bus
• 2: tsl2561.TSL2561_ERROR_I2CBUSY: I2C bus busy
• 3: tsl2561.TSL2561_ERROR_NOINIT: Initialize I2C bus before calling function
• 4: tsl2561.TSL2561_ERROR_LAST

Example

status = tsl2561.init(5,6,tsl2561.ADDRESS_FLOAT, tsl2561.PACKAGE_T_FN_CL)
if (status == 0) then
  status = tsl2561.settiming(tsl2561.INTEGRATIONTIME_101MS, tsl2561.GAIN_16X)
end
if (status == 0) then
  lux = tsl2561.getlux()
  print("Illuminance: "..lux.." lx") 
end

tsl2561.getlux()

Description

Reads sensor values from the device and returns calculated lux value.

Syntax

tsl2561.getlux()

Parameters

nil

Return

• lux: The calculated illuminance in lux (lx).
• status: value indicating success or failure as explained below
  • 0: tsl2561.TSL2561_OK
  • 1: tsl2561.TSL2561_ERROR_I2CINIT: Can't initialize I2C bus
  • 2: tsl2561.TSL2561_ERROR_I2CBUSY: I2C bus busy
  • 3: tsl2561.TSL2561_ERROR_NOINIT: Initialize I2C bus before calling function
  • 4: tsl2561.TSL2561_ERROR_LAST

Example

status = tsl2561.init(5,6,tsl2561.ADDRESS_FLOAT, tsl2561.PACKAGE_T_FN_CL)

if (status == 0) then
  lux = tsl2561.getlux()
  print("Illuminance: "..lux.." lx") 
end

tsl2561.getrawchannels()

Description

Reads the device's 2 sensors and returns their values.

Syntax

tsl2561.getrawchannels()

Parameters

nil

Return

• ch0: Value of the broad spectrum sensor
• ch1: Value of the IR sensor
• status: value indicating success or failure as explained below
  • 0: tsl2561.TSL2561_OK
  • 1: tsl2561.TSL2561_ERROR_I2CINIT: Can't initialize I2C bus
  • 2: tsl2561.TSL2561_ERROR_I2CBUSY: I2C bus busy
  • 3: tsl2561.TSL2561_ERROR_NOINIT: Initialize I2C bus before calling function
  • 4: tsl2561.TSL2561_ERROR_LAST

Example

status = tsl2561.init(5,6,tsl2561.ADDRESS_FLOAT, tsl2561.PACKAGE_T_FN_CL)

if (status == 0) then
  ch0, ch1 = tsl2561.getrawchannels()
  print("Raw values: "..ch0,ch1)
  lux = tsl2561.getlux()
  print("Illuminance: "..lux.." lx") 
end