int TSL2561_OPEN(TSL2561 *sensor) {
char filename[20];
if(sensor->adapter_fd != -1) { // already opened
// TODO: choose a valid errno error
sensor->lasterr = -1;
return -1;
}
snprintf(filename, 20, "/dev/i2c-%d", sensor->adapter_nr);
if ((sensor->adapter_fd = open(filename, O_RDWR)) < 0) { // open the device file (requests i2c-dev kernel module loaded)
sensor->lasterr = errno;
return -1;
}
if (ioctl(sensor->adapter_fd, I2C_SLAVE, sensor->sensor_addr) < 0) { // talk to the requested device
sensor->lasterr = errno;
close(sensor->adapter_fd);
sensor->adapter_fd = -1;
return -1;
}
TSL2561_SETINTEGRATIONTIME(sensor, TSL2561_INTEGRATIONTIME_402MS);
TSL2561_SETGAIN(sensor, TSL2561_GAIN_16X);
/*
TSL2561_ON(sensor);
tsl2561_write8(sensor, 0x81, 0x11);
TSL2561_OFF(sensor);
*/
return 0;
}
int main() {
int rc;
uint16_t broadband, ir;
uint32_t lux=0;
// prepare the sensor
// (the first parameter is the raspberry pi i2c master controller attached to the TSL2561, the second is the i2c selection jumper)
// The i2c selection address can be one of: TSL2561_ADDR_LOW, TSL2561_ADDR_FLOAT or TSL2561_ADDR_HIGH
TSL2561 light1 = TSL2561_INIT(1, TSL2561_ADDR_FLOAT);
// initialize the sensor
rc = TSL2561_OPEN(&light1);
if(rc != 0) {
fprintf(stderr, "Error initializing TSL2561 sensor (%s). Check your i2c bus (es. i2cdetect)\n", strerror(light1.lasterr));
// you don't need to TSL2561_CLOSE() if TSL2561_OPEN() failed, but it's safe doing it.
TSL2561_CLOSE(&light1);
return 1;
}
// set the gain to 1X (it can be TSL2561_GAIN_1X or TSL2561_GAIN_16X)
// use 16X gain to get more precision in dark ambients, or enable auto gain below
rc = TSL2561_SETGAIN(&light1, TSL2561_GAIN_1X);
// set the integration time
// (TSL2561_INTEGRATIONTIME_402MS or TSL2561_INTEGRATIONTIME_101MS or TSL2561_INTEGRATIONTIME_13MS)
// TSL2561_INTEGRATIONTIME_402MS is slower but more precise, TSL2561_INTEGRATIONTIME_13MS is very fast but not so precise
rc = TSL2561_SETINTEGRATIONTIME(&light1, TSL2561_INTEGRATIONTIME_101MS);
// sense the luminosity from the sensor (lux is the luminosity taken in "lux" measure units)
// the last parameter can be 1 to enable library auto gain, or 0 to disable it
rc = TSL2561_SENSELIGHT(&light1, &broadband, &ir, &lux, 1);
printf("Test. RC: %i(%s), broadband: %i, ir: %i, lux: %i\n", rc, strerror(light1.lasterr), broadband, ir, lux);
TSL2561_CLOSE(&light1);
return 0;
}
/**
* sense the ambient light. Returns 0 on success, -1 on errors.
* the parameter pointer fullspectrum is the quantity og light at full spectrum (including infrared)
* the parameter pointer infrared is the quantity of infrared light
* if autogain is 0 a single sensor reading is done with the gain and integration time previously selected by invoking
* the TSL2561_SETINTEGRATIONTIME() and TSL2561_SETGAIN() functions. It autogain is 1 and automatic gain adjustment alghoritm is used
*/
int TSL2561_SENSELIGHT(TSL2561 *sensor, uint16_t *full_spectrum, uint16_t *infrared, uint32_t *lux, int autogain) {
int rc=1;
uint16_t fs, ir, hi, lo;
//tsl2561Gain_t old_gain;
if(sensor->adapter_fd == -1) {
// TODO: choose a valid errno error
sensor->lasterr = -1;
return -1;
}
if (autogain == 0) { // autogain not requested. Executing a single sensor read
rc = tsl2561_getdata(sensor, full_spectrum, infrared);
*lux = TSL2561_CALCULATE_LUX(sensor, *full_spectrum, *infrared);
return rc;
}
// autogain requested
switch(sensor->integration_time) {
case TSL2561_INTEGRATIONTIME_13MS:
hi = TSL2561_AGC_THI_13MS;
lo = TSL2561_AGC_TLO_13MS;
break;
case TSL2561_INTEGRATIONTIME_101MS:
hi = TSL2561_AGC_THI_101MS;
lo = TSL2561_AGC_TLO_101MS;
break;
case TSL2561_INTEGRATIONTIME_402MS:
hi = TSL2561_AGC_THI_402MS;
lo = TSL2561_AGC_TLO_402MS;
break;
default:
hi = TSL2561_AGC_THI_402MS;
lo = TSL2561_AGC_TLO_402MS;
break;
}
// save the old gain
//old_gain = sensor->gain;
// try to adjust the gain
rc = tsl2561_getdata(sensor, &fs, &ir);
if(rc != 0) {
return -1; // invalid read or sensor error
}
if ((fs < lo) && (sensor->gain == TSL2561_GAIN_1X)) { // light too low with this gain
// raise the gain and redo the reading
TSL2561_SETGAIN(sensor, TSL2561_GAIN_16X);
//printf("gain raised\n");
rc = tsl2561_getdata(sensor, &fs, &ir);
// restore the previous gain
//TSL2561_SETGAIN(sensor, old_gain);
if(rc != 0) { // invalid read or sensor error
return -1;
} else {
// now consider the reading valid after being adjusted
*full_spectrum = fs;
*infrared = ir;
*lux = TSL2561_CALCULATE_LUX(sensor, *full_spectrum, *infrared);
return 0;
}
}
if ((fs > hi) && (sensor->gain == TSL2561_GAIN_16X)) { // light too high with this gain
// lower the gain and redo the reading
TSL2561_SETGAIN(sensor, TSL2561_GAIN_1X);
//printf("gain lowered\n");
rc = tsl2561_getdata(sensor, &fs, &ir);
// restore the previous gain
//TSL2561_SETGAIN(sensor, old_gain);
if(rc != 0) { // invalid read or sensor error
return -1;
} else {
// now consider the reading valid after being adjusted
*full_spectrum = fs;
*infrared = ir;
*lux = TSL2561_CALCULATE_LUX(sensor, *full_spectrum, *infrared);
return 0;
}
}
// the reading was valid without gain adjustment (or chip limits encountered!)
*full_spectrum = fs;
*infrared = ir;
*lux = TSL2561_CALCULATE_LUX(sensor, *full_spectrum, *infrared);
return 0;
}
