115 lines
5.1 KiB
C++
115 lines
5.1 KiB
C++
#ifndef BH1750FVI_h
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#define BH1750FVI_h
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//#if ARDUINO >= 100
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#include "Arduino.h"
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//#else
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// #include "WProgram.h"
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//#endif
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#include <Wire.h>
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//device address options
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#define BH_AddrL 0x23 // Device address when addr pin is LOW
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#define BH_AddrH 0x5C // Device address when addr pin is HIGH
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//power codes
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#define BH_PowOf 0x00 // power-off code
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#define BH_PowOn 0x01 // power-on code
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#define BH_Reset 0x07 // code to reset the light reading register to zero
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//mode codes
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#define BH_NoMod 0x02 // No mode specified. Keeps mode the same as before.
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#define BH_EasyH 0x03 // 'easy' mode. basically the same as ContH
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#define BH_ContH 0x10 // continuous full-scale, high-resolution sampling
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#define BH_Conth 0x11 // continuous with twice the resolution but half the max value
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#define BH_ContL 0x13 // continuous full-scale, low-resolution sampling. faster.
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#define BH_SingH 0x20 // take one high-resolution, full-scale sample then turn off
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#define BH_Singh 0x21 // take one high-resolution, half-scale sample then turn off
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#define BH_SingL 0x23 // take one low-resolution, full-scale sample then turn off
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// (happens to be the same as the low address value)
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//sensitivity codes
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#define BH_MTrHb 0x40 // last 3 bits must be masked to 3 MSB of desired value
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#define BH_MTrLb 0x60 // last 5 bits must be masked to 5 LSB of desired value
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#define BH_MinSv 31 // minimum sensitivity register value, yields Lux * 0.45
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#define BH_MaxSv 254 // maximum sensitivity register value, yields Lux * 3.68
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#define BH_DefSv 69 // default sensitivity register value, yields Lux * 1.00
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//timing delays. they're actually longer than the datasheet says.
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#define BH_FastD 18 // basic delay in microseconds for a fast sample
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#define BH_SlowD 125 // basic delay in microseconds for a slow sample
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class BH1750FVI {
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public:
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/*BEGIN
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this is intended to be as error-tolerant as possible. if you don't supply
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a mode, the default mode will be 'easy'. the sensitivity obviously defaults
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to 1.0 (byte value of 69). Default address selection is LOW, which is how
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the BH1750FVI should default if you don't connect anything to its ADDR pin.
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*/void begin(byte mode=BH_EasyH, byte addr=BH_AddrL, double sens=BH_DefSv, int addrPin=-1);
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/*FRESH SAMPLE POLLING
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Check whether you have already looked at the current sample.
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*/bool sampleIsFresh();
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/*ACTUALLY GET A READING FROM THE SENSOR
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This is probably all you wanted from this library. Return value is an
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unsigned 16 bit integer with units of Lux. There are three possible modes:
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'r' raw numerical reading, no units, you get what you get
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'c' convert units to Lux or half-Lux, depending on the mode, but don't
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compensate for the sensitivity setting. This allows sensitivity to
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be used as enclosure optics calibration/compensation.
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't' true Lux (or half-Lux) reading, regardless of sensitivity settings.
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*/word getLightLevel(char adjustments='c');
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word retrieveSample();
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/*CONTINUOUS SAMPLING
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Return value of this start function is the delay time between refreshes of
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the ambient light reading. After you call this function, you can use getLightLevel()
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to read the most recent ambient light level. If you try to run this ongoing start
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function with a one-time mode argument, it will do nothing and return 0.
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*/word startOngoingSamples(char mode=BH_NoMod);
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/*ONE-TIME SAMPLE START
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Return value of this start function is the delay time before the new ambient
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light reading will be available. You can check whether the new sample is ready
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yet using sampleIsFresh(). Retrieve that single sample with getLightLevel().
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If you give this one-time start function a continuous mode argument, it will
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do nothing and return 0.
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*/word startSingleSample(char mode=BH_NoMod);
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/*SENSITIVITY SETTINGS
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This function lets you change the 'sensitivity' of the BH1750FVI by changing
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its sampling time up or down. The sensitivity is stored as a number between
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31 and 254, with a default value of 69. This is intended to compensate for
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having the chip installed in an enclosure that blocks some ambient light.
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The floating point versions of the function allow the sensitivity to be
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given as a ratio between ~0.45 and ~3.68. The return value is the number of
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milliseconds that the chip will take to create a new light level reading.
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*/word setSensitivity(double sens);
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word setSensitivity(float sens);
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word setSensitivity(int sens);
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word setSensitivity(byte sens=BH_DefSv);
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/*POWERDOWN FUNCTION
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In case you want to turn off the BH1750FVI to save power. Other commands will wake
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the chip back up. Single sample modes automatically turn off the chip after sampling,
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but you can still read the value from it without waking it up.
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*/void powerDown();
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private:
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void init(byte mode, byte addr, byte sens);
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void i2cWrite(byte dataToSend);
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word i2cRead();
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byte address;
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byte currentMode;
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byte currentSensitivity;
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bool sampleUnseen;
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byte MTreg_hiByte;
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byte MTreg_loByte;
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unsigned long int lastSampleStart;
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word currentSamplingTime;
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};
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#endif
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