Hello particle community.
I am having a tough time verifying the validity of the lux measurements obtained from my TSL2561 lux sensor.
When i use the adafruit code and library i obtain measurements that are, in general, half the values i measure using the control everything’s code and library.
Here is the code from adafruit:
//#include <Adafruit_TSL2561_U.h>
/* This driver uses the Adafruit unified sensor library (Adafruit_Sensor),
which provides a common 'type' for sensor data and some helper functions.
To use this driver you will also need to download the Adafruit_Sensor
library and include it in your libraries folder.
You should also assign a unique ID to this sensor for use with
the Adafruit Sensor API so that you can identify this particular
sensor in any data logs, etc. To assign a unique ID, simply
provide an appropriate value in the constructor below (12345
is used by default in this example).
Connections
===========
Connect SCL to analog 5
Connect SDA to analog 4
Connect VDD to 3.3V DC
Connect GROUND to common ground
I2C Address
===========
The address will be different depending on whether you leave
the ADDR pin floating (addr 0x39), or tie it to ground or vcc.
The default addess is 0x39, which assumes the ADDR pin is floating
(not connected to anything). If you set the ADDR pin high
or low, use TSL2561_ADDR_HIGH (0x49) or TSL2561_ADDR_LOW
(0x29) respectively.
History
=======
2013/JAN/31 - First version (KTOWN)
*/
Adafruit_TSL2561_Unified tsl = Adafruit_TSL2561_Unified(TSL2561_ADDR_FLOAT, 0x39);
/**************************************************************************/
/*
Displays some basic information on this sensor from the unified
sensor API sensor_t type (see Adafruit_Sensor for more information)
*/
/**************************************************************************/
void displaySensorDetails(void)
{
sensor_t sensor;
tsl.getSensor(&sensor);
Serial.println("------------------------------------");
Serial.print ("Sensor: "); Serial.println(sensor.name);
Serial.print ("Driver Ver: "); Serial.println(sensor.version);
Serial.print ("Unique ID: "); Serial.println(sensor.sensor_id);
Serial.print ("Max Value: "); Serial.print(sensor.max_value); Serial.println(" lux");
Serial.print ("Min Value: "); Serial.print(sensor.min_value); Serial.println(" lux");
Serial.print ("Resolution: "); Serial.print(sensor.resolution); Serial.println(" lux");
Serial.println("------------------------------------");
Serial.println("");
delay(500);
}
/**************************************************************************/
/*
Configures the gain and integration time for the TSL2561
*/
/**************************************************************************/
void configureSensor(void)
{
/* You can also manually set the gain or enable auto-gain support */
//tsl.setGain(TSL2561_GAIN_1X); /* No gain ... use in bright light to avoid sensor saturation */
//tsl.setGain(TSL2561_GAIN_16X); /* 16x gain ... use in low light to boost sensitivity */
tsl.enableAutoRange(true); /* Auto-gain ... switches automatically between 1x and 16x */
/* Changing the integration time gives you better sensor resolution (402ms = 16-bit data) */
//tsl.setIntegrationTime(TSL2561_INTEGRATIONTIME_13MS); /* fast but low resolution */
//tsl.setIntegrationTime(TSL2561_INTEGRATIONTIME_101MS); /* medium resolution and speed */
tsl.setIntegrationTime(TSL2561_INTEGRATIONTIME_402MS); /* 16-bit data but slowest conversions */
/* Update these values depending on what you've set above! */
Serial.println("------------------------------------");
Serial.print ("Gain: "); Serial.println("Auto");
Serial.print ("Timing: "); Serial.println("13 ms");
Serial.println("------------------------------------");
}
/**************************************************************************/
/*
Arduino setup function (automatically called at startup)
*/
/**************************************************************************/
void setup(void)
{
Serial.begin(9600);
Serial.println("Light Sensor Test"); Serial.println("");
/* Initialise the sensor */
if(!tsl.begin())
{
/* There was a problem detecting the ADXL345 ... check your connections */
Serial.print("Ooops, no TSL2561 detected ... Check your wiring or I2C ADDR!");
while(1);
}
else if(tsl.begin()){
/* Display some basic information on this sensor */
displaySensorDetails();
/* Setup the sensor gain and integration time */
configureSensor();
/* We're ready to go! */
Serial.println("Ready");
}
}
/**************************************************************************/
/*
Arduino loop function, called once 'setup' is complete (your own code
should go here)
*/
/**************************************************************************/
void loop(void)
{
/* Get a new sensor event */
sensors_event_t event;
tsl.getEvent(&event);
/* Display the results (light is measured in lux) */
if (event.light)
{
Serial.print(event.light); Serial.println(" lux");
}
else
{
/* If event.light = 0 lux the sensor is probably saturated
and no reliable data could be generated! */
Serial.println("Sensor overload");
}
delay(250);
}
####################################################
####################################################
####################################################
This is control everything's code from github:
// Distributed with a free-will license.
// Use it any way you want, profit or free, provided it fits in the licenses of its associated works.
// TSL2561
// This code is designed to work with the TSL2561_I2CS I2C Mini Module available from ControlEverything.com.
// https://www.controleverything.com/content/Light?sku=TSL2561_I2CS#tabs-0-product_tabset-2
#include<Wire.h>
// TSL2561 I2C address is 0x39(57)
#define Addr 0x39
void setup()
{
// Initialise I2C communication as MASTER
Wire.begin();
// Initialise serial communication, set baud rate = 9600
Serial.begin(9600);
// Starts I2C communication
Wire.beginTransmission(Addr);
// Select control register
Wire.write(0x00 | 0x80);
// Power ON mode
Wire.write(0x03);
// Stop I2C Transmission
Wire.endTransmission();
// Starts I2C communication
Wire.beginTransmission(Addr);
// Select timing register
Wire.write(0x01 | 0x80);
// Nominal integration time = 402ms
Wire.write(0x02);
// Stop I2C Transmission
Wire.endTransmission();
delay(300);
}
void loop()
{
unsigned int data[4];
for(int i = 0; i < 4; i++) // *****why i=4??
{
// Starts I2C communication
Wire.beginTransmission(Addr);
// Select data register
Wire.write((140 + i));
// Stop I2C Transmission
Wire.endTransmission();
// Request 1 byte of data
Wire.requestFrom(Addr, 1);
// Read 1 bytes of data
if(Wire.available() == 1)
{
data[i] = Wire.read();
}
delay(200);
}
// Convert the data
double ch0 = ((data[1] & 0xFF) * 256) + (data[0] & 0xFF);
double ch1 = ((data[3] & 0xFF) * 256) + (data[2] & 0xFF);
// Output data to serial monitor
Serial.print("Full Spectrum(IR + Visible) :");
Serial.println(ch0);
Serial.print("Infrared Value :");
Serial.println(ch1);
Serial.print("Visible Value :");
Serial.println(ch0-ch1);
}
When i tried changing the gain and the integration time using adafruit’s code my sensor measures an overload condition. It only works when the gain is set to automatic and when the integration time is 13ms.
Also the TSL2561 I purchased is not the adafruit brand. I am not sure if this is the reason why the readings are ‘incorrect’ when compared to the readings using CE’s code. Although this should not impact the accuracy of the measurements. Has anyone else experienced this issue ?
