This is an Arduino library for the TSL2561 digital luminosity (light) sensors.

Pick one up at http://www.adafruit.com/products/xxx

To download. click the DOWNLOADS button in the top right corner, rename the uncompressed folder TSL2561. Check that the TSL2561 folder contains TSL2561.cpp and TSL2561.h

Place the TSL2561 library folder your <arduinosketchfolder>/libraries/ folder. You may need to create the libraries subfolder if its your first library. Restart the IDE.

#include <avr/pgmspace.h>

#include <WProgram.h>

#include <util/delay.h>

#include <stdlib.h>

#include <Wire.h>

#include "TSL2561.h"

TSL2561::TSL2561(uint8_t addr) {

_addr = addr;

_initialized = false;

_integration = TSL2561_INTEGRATIONTIME_13MS;

_gain = TSL2561_GAIN_16X;

// we cant do wire initialization till later, because we havent loaded Wire yet

}

boolean TSL2561::begin(void) {

Wire.begin();

// Initialise I2C

Wire.beginTransmission(_addr);

Wire.send(TSL2561_REGISTER_ID);

Wire.endTransmission();

Wire.requestFrom(_addr, 1);

int x = Wire.receive();

//Serial.print("0x"); Serial.println(x, HEX);

if (x & 0x0A ) {

//Serial.println("Found TSL2561");

} else {

return false;

}

_initialized = true;

// Set default integration time and gain

setTiming(_integration);

setGain(_gain);

// Note: by default, the device is in power down mode on bootup

disable();

return true;

}

void TSL2561::enable(void)

{

if (!_initialized) begin();

// Enable the device by setting the control bit to 0x03

write8(TSL2561_COMMAND_BIT | TSL2561_REGISTER_CONTROL, TSL2561_CONTROL_POWERON);

}

void TSL2561::disable(void)

{

if (!_initialized) begin();

// Disable the device by setting the control bit to 0x03

write8(TSL2561_COMMAND_BIT | TSL2561_REGISTER_CONTROL, TSL2561_CONTROL_POWEROFF);

}

void TSL2561::setGain(tsl2561Gain_t gain) {

if (!_initialized) begin();

enable();

_gain = gain;

write8(TSL2561_COMMAND_BIT | TSL2561_REGISTER_TIMING, _integration | _gain);

disable();

}

void TSL2561::setTiming(tsl2561IntegrationTime_t integration)

{

if (!_initialized) begin();

enable();

_integration = integration;

write8(TSL2561_COMMAND_BIT | TSL2561_REGISTER_TIMING, _integration | _gain);

disable();

}

uint32_t TSL2561::calculateLux(uint16_t ch0, uint16_t ch1)

{

unsigned long chScale;

unsigned long channel1;

unsigned long channel0;

switch (_integration)

{

case TSL2561_INTEGRATIONTIME_13MS:

chScale = TSL2561_LUX_CHSCALE_TINT0;

break;

case TSL2561_INTEGRATIONTIME_101MS:

chScale = TSL2561_LUX_CHSCALE_TINT1;

break;

default: // No scaling ... integration time = 402ms

chScale = (1 << TSL2561_LUX_CHSCALE);

break;

}

// Scale for gain (1x or 16x)

if (!_gain) chScale = chScale << 4;

// scale the channel values

channel0 = (ch0 * chScale) >> TSL2561_LUX_CHSCALE;

channel1 = (ch1 * chScale) >> TSL2561_LUX_CHSCALE;

// find the ratio of the channel values (Channel1/Channel0)

unsigned long ratio1 = 0;

if (channel0 != 0) ratio1 = (channel1 << (TSL2561_LUX_RATIOSCALE+1)) / channel0;

// round the ratio value

unsigned long ratio = (ratio1 + 1) >> 1;

unsigned int b, m;

#ifdef TSL2561_PACKAGE_CS

if ((ratio >= 0) && (ratio <= TSL2561_LUX_K1C))

{b=TSL2561_LUX_B1C; m=TSL2561_LUX_M1C;}

else if (ratio <= TSL2561_LUX_K2C)

{b=TSL2561_LUX_B2C; m=TSL2561_LUX_M2C;}

else if (ratio <= TSL2561_LUX_K3C)

{b=TSL2561_LUX_B3C; m=TSL2561_LUX_M3C;}

else if (ratio <= TSL2561_LUX_K4C)

{b=TSL2561_LUX_B4C; m=TSL2561_LUX_M4C;}

else if (ratio <= TSL2561_LUX_K5C)

{b=TSL2561_LUX_B5C; m=TSL2561_LUX_M5C;}

else if (ratio <= TSL2561_LUX_K6C)

{b=TSL2561_LUX_B6C; m=TSL2561_LUX_M6C;}

else if (ratio <= TSL2561_LUX_K7C)

{b=TSL2561_LUX_B7C; m=TSL2561_LUX_M7C;}

else if (ratio > TSL2561_LUX_K8C)

{b=TSL2561_LUX_B8C; m=TSL2561_LUX_M8C;}

#else

if ((ratio >= 0) && (ratio <= TSL2561_LUX_K1T))

{b=TSL2561_LUX_B1T; m=TSL2561_LUX_M1T;}

else if (ratio <= TSL2561_LUX_K2T)

{b=TSL2561_LUX_B2T; m=TSL2561_LUX_M2T;}

else if (ratio <= TSL2561_LUX_K3T)

{b=TSL2561_LUX_B3T; m=TSL2561_LUX_M3T;}

else if (ratio <= TSL2561_LUX_K4T)

{b=TSL2561_LUX_B4T; m=TSL2561_LUX_M4T;}

else if (ratio <= TSL2561_LUX_K5T)

{b=TSL2561_LUX_B5T; m=TSL2561_LUX_M5T;}

else if (ratio <= TSL2561_LUX_K6T)

{b=TSL2561_LUX_B6T; m=TSL2561_LUX_M6T;}

else if (ratio <= TSL2561_LUX_K7T)

{b=TSL2561_LUX_B7T; m=TSL2561_LUX_M7T;}

else if (ratio > TSL2561_LUX_K8T)

{b=TSL2561_LUX_B8T; m=TSL2561_LUX_M8T;}

#endif

unsigned long temp;

temp = ((channel0 * b) - (channel1 * m));

// do not allow negative lux value

if (temp < 0) temp = 0;

// round lsb (2^(LUX_SCALE-1))

temp += (1 << (TSL2561_LUX_LUXSCALE-1));

// strip off fractional portion

uint32_t lux = temp >> TSL2561_LUX_LUXSCALE;

// Signal I2C had no errors

return lux;

}

uint32_t TSL2561::getFullLuminosity (void)

{

if (!_initialized) begin();

// Enable the device by setting the control bit to 0x03

enable();

// Wait x ms for ADC to complete

switch (_integration)

{

case TSL2561_INTEGRATIONTIME_13MS:

delay(14);

break;

case TSL2561_INTEGRATIONTIME_101MS:

delay(102);

break;

default:

delay(400);

break;

}

uint32_t x;

x = read16(TSL2561_COMMAND_BIT | TSL2561_WORD_BIT | TSL2561_REGISTER_CHAN1_LOW);

x <<= 16;

x |= read16(TSL2561_COMMAND_BIT | TSL2561_WORD_BIT | TSL2561_REGISTER_CHAN0_LOW);

disable();

return x;

}

uint16_t TSL2561::getLuminosity (uint8_t channel) {

uint32_t x = getFullLuminosity();

if (channel == 0) {

// Reads two byte value from channel 0 (visible + infrared)

return (x & 0xFFFF);

} else if (channel == 1) {

// Reads two byte value from channel 1 (infrared)

return (x >> 16);

} else if (channel == 2) {

// Reads all and subtracts out just the visible!

return ( (x & 0xFFFF) - (x >> 16));

}

// unknown channel!

return 0;

}

uint16_t TSL2561::read16(uint8_t reg)

{

uint16_t x; uint16_t t;

Wire.beginTransmission(_addr);

Wire.send(reg);

Wire.endTransmission();

Wire.requestFrom(_addr, 2);

t = Wire.receive();

x = Wire.receive();

x <<= 8;

x |= t;

return x;

}

void TSL2561::write8 (uint8_t reg, uint8_t value)

{

Wire.beginTransmission(_addr);

Wire.send(reg);

Wire.send(value);

Wire.endTransmission();

}