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101 lines
2.8 KiB
C++

// Sketch to explore the luminosity sensor TSL2561 (breakout board by Adafruit)
#define SDA_PORT PORTD
#define SDA_PIN 3
#define SCL_PORT PORTD
#define SCL_PIN 5
#include <SoftI2CMaster.h>
#include "TSL2561Soft.h"
#define ADDR 0x72
//------------------------------------------------------------------------------
unsigned long computeLux(unsigned long channel0, unsigned long channel1){
/* Make sure the sensor isn't saturated! */
uint16_t clipThreshold = TSL2561_CLIPPING_402MS;;
/* Return 0 lux if the sensor is saturated */
if ((channel0 > clipThreshold) || (channel1 > clipThreshold))
{
Serial.println(F("Sensor is saturated"));
return 32000;
}
/* 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;
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;}
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;
return lux;
}
void setup(void) {
Serial.begin(19200);
Serial.println("Initializing ...");
i2c_init();
if (!i2c_start(ADDR | I2C_WRITE)) Serial.println(F("Device does not respond"));
if (!i2c_write(0x80)) Serial.println(F("Cannot address reg 0"));
if (!i2c_write(0x03)) Serial.println(F("Cannot wake up"));
i2c_stop();
}
void loop (void) {
unsigned int low0, high0, low1, high1;
unsigned int chan0, chan1;
unsigned int lux;
delay(1000);
i2c_start(ADDR | I2C_WRITE);
i2c_write(0x8C);
i2c_rep_start(ADDR | I2C_READ);
low0 = i2c_read(false);
high0 = i2c_read(false);
low1 = i2c_read(false);
high1 = i2c_read(true);
i2c_stop();
Serial.print(F("Raw values: chan0="));
Serial.print(chan0=(low0+(high0<<8)));
Serial.print(F(" / chan1="));
Serial.println(chan1=(low1+(high1<<8)));
lux = computeLux(chan0,chan1);
Serial.print(F("Lux value="));
Serial.println(lux);
}