287 lines
8.3 KiB
C++
287 lines
8.3 KiB
C++
/*
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This is a library for the BH1750_SoftFVI Digital Light Sensor breakout board.
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The BH1750_Soft board uses I2C for communication. Two pins are required to
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interface to the device. Configuring the I2C bus is expected to be done
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in user code. The BH1750_Soft library doesn't do this automatically.
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Written by Christopher Laws, March, 2013.
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*/
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#include "BH1750_Soft.h"
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#include <SoftwareWire.h>
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// Define milliseconds delay for ESP8266 platform
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#if defined(ESP8266)
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#include <pgmspace.h>
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#define _delay_ms(ms) delayMicroseconds((ms) * 1000)
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// Use _delay_ms from utils for AVR-based platforms
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#elif defined(__avr__)
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#include <util/delay.h>
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// Use Wiring's delay for compability with another platforms
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#else
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#define _delay_ms(ms) delay(ms)
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#endif
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// Legacy Wire.write() function fix
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#if (ARDUINO >= 100)
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#define __wire_write(d) _wire->write(d)
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#else
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#define __wire_write(d) _wire->send(d)
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#endif
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// Legacy Wire.read() function fix
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#if (ARDUINO >= 100)
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#define __wire_read() _wire->read()
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#else
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#define __wire_read() _wire->receive()
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#endif
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/**
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* Constructor
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* @params addr Sensor address (0x76 or 0x72, see datasheet)
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*
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* On most sensor boards, it was 0x76
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*/
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BH1750_Soft::BH1750_Soft() {}
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/**
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* Configure sensor
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* @param mode Measurement mode
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*/
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bool BH1750_Soft::begin(Mode mode, byte addr, SoftwareWire *theWire) {
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_wire = theWire;
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BH1750_Soft_I2CADDR = addr;
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// I2C is expected to be initialized outside this library
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// Configure sensor in specified mode
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return configure(mode);
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}
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/**
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* Configure BH1750_Soft with specified mode
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* @param mode Measurement mode
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*/
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bool BH1750_Soft::configure(Mode mode) {
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// default transmission result to a value out of normal range
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byte ack = 5;
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// Check measurement mode is valid
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switch (mode) {
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case BH1750_Soft::CONTINUOUS_HIGH_RES_MODE:
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case BH1750_Soft::CONTINUOUS_HIGH_RES_MODE_2:
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case BH1750_Soft::CONTINUOUS_LOW_RES_MODE:
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case BH1750_Soft::ONE_TIME_HIGH_RES_MODE:
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case BH1750_Soft::ONE_TIME_HIGH_RES_MODE_2:
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case BH1750_Soft::ONE_TIME_LOW_RES_MODE:
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// Send mode to sensor
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_wire->beginTransmission(BH1750_Soft_I2CADDR);
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__wire_write((uint8_t)BH1750_Soft_MODE);
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ack = _wire->endTransmission();
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// Wait a few moments to wake up
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_delay_ms(10);
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break;
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default:
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// Invalid measurement mode
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Serial.println(F("[BH1750_Soft] ERROR: Invalid mode"));
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break;
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}
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// Check result code
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switch (ack) {
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case 0:
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BH1750_Soft_MODE = mode;
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return true;
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case 1: // too long for transmit buffer
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Serial.println(F("[BH1750_Soft] ERROR: too long for transmit buffer"));
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break;
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case 2: // received NACK on transmit of address
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Serial.println(F("[BH1750_Soft] ERROR: received NACK on transmit of address"));
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break;
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case 3: // received NACK on transmit of data
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Serial.println(F("[BH1750_Soft] ERROR: received NACK on transmit of data"));
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break;
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case 4: // other error
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Serial.println(F("[BH1750_Soft] ERROR: other error"));
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break;
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default:
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Serial.println(F("[BH1750_Soft] ERROR: undefined error"));
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break;
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}
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return false;
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}
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/**
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* Configure BH1750_Soft MTreg value
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* MT reg = Measurement Time register
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* @param MTreg a value between 32 and 254. Default: 69
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* @return bool true if MTReg successful set
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* false if MTreg not changed or parameter out of range
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*/
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bool BH1750_Soft::setMTreg(byte MTreg) {
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//Bug: lowest value seems to be 32!
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if (MTreg <= 31 || MTreg > 254) {
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Serial.println(F("[BH1750_Soft] ERROR: MTreg out of range"));
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return false;
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}
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byte ack = 5;
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// Send MTreg and the current mode to the sensor
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// High bit: 01000_MT[7,6,5]
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// Low bit: 011_MT[4,3,2,1,0]
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_wire->beginTransmission(BH1750_Soft_I2CADDR);
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__wire_write((0b01000 << 3) | (MTreg >> 5));
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ack = _wire->endTransmission();
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_wire->beginTransmission(BH1750_Soft_I2CADDR);
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__wire_write((0b011 << 5 ) | (MTreg & 0b11111));
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ack = ack | _wire->endTransmission();
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_wire->beginTransmission(BH1750_Soft_I2CADDR);
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__wire_write(BH1750_Soft_MODE);
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ack = ack | _wire->endTransmission();
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// Wait a few moments to wake up
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_delay_ms(10);
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// Check result code
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switch (ack) {
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case 0:
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BH1750_Soft_MTreg = MTreg;
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// Delay for specific continuous mode to get valid values
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switch (BH1750_Soft_MODE) {
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case BH1750_Soft::CONTINUOUS_LOW_RES_MODE:
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_delay_ms(24 * BH1750_Soft_MTreg/(byte)BH1750_Soft_DEFAULT_MTREG);
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break;
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case BH1750_Soft::CONTINUOUS_HIGH_RES_MODE:
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case BH1750_Soft::CONTINUOUS_HIGH_RES_MODE_2:
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_delay_ms(180 * BH1750_Soft_MTreg/(byte)BH1750_Soft_DEFAULT_MTREG);
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break;
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default:
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break;
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}
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return true;
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case 1: // too long for transmit buffer
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Serial.println(F("[BH1750_Soft] ERROR: too long for transmit buffer"));
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break;
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case 2: // received NACK on transmit of address
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Serial.println(F("[BH1750_Soft] ERROR: received NACK on transmit of address"));
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break;
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case 3: // received NACK on transmit of data
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Serial.println(F("[BH1750_Soft] ERROR: received NACK on transmit of data"));
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break;
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case 4: // other error
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Serial.println(F("[BH1750_Soft] ERROR: other error"));
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break;
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default:
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Serial.println(F("[BH1750_Soft] ERROR: undefined error"));
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break;
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}
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return false;
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}
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/**
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* Read light level from sensor
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* The return value range differs if the MTreg value is changed. The global
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* maximum value is noted in the square brackets.
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* @return Light level in lux (0.0 ~ 54612,5 [117758,203])
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* -1 : no valid return value
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* -2 : sensor not configured
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*/
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float BH1750_Soft::readLightLevel(bool maxWait) {
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if (BH1750_Soft_MODE == UNCONFIGURED) {
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Serial.println(F("[BH1750_Soft] Device is not configured!"));
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return -2.0;
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}
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// Measurement result will be stored here
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float level = -1.0;
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// Send mode to sensor
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_wire->beginTransmission(BH1750_Soft_I2CADDR);
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__wire_write((uint8_t)BH1750_Soft_MODE);
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_wire->endTransmission();
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// Wait for measurement to be taken.
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// Measurements have a maximum measurement time and a typical measurement
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// time. The maxWait argument determines which measurement wait time is
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// used when a one-time mode is being used. The typical (shorter)
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// measurement time is used by default and if maxWait is set to True then
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// the maximum measurement time will be used. See data sheet pages 2, 5
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// and 7 for more details.
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// A continuous mode measurement can be read immediately after re-sending
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// the mode command.
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switch (BH1750_Soft_MODE) {
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case BH1750_Soft::ONE_TIME_LOW_RES_MODE:
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maxWait ? _delay_ms(24 * BH1750_Soft_MTreg/(byte)BH1750_Soft_DEFAULT_MTREG) : _delay_ms(16 * BH1750_Soft_MTreg/(byte)BH1750_Soft_DEFAULT_MTREG);
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break;
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case BH1750_Soft::ONE_TIME_HIGH_RES_MODE:
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case BH1750_Soft::ONE_TIME_HIGH_RES_MODE_2:
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maxWait ? _delay_ms(180 * BH1750_Soft_MTreg/(byte)BH1750_Soft_DEFAULT_MTREG) :_delay_ms(120 * BH1750_Soft_MTreg/(byte)BH1750_Soft_DEFAULT_MTREG);
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break;
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default:
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break;
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}
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// Read two bytes from the sensor, which are low and high parts of the sensor
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// value
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if (2 == _wire->requestFrom((int)BH1750_Soft_I2CADDR, (int)2)) {
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unsigned int tmp = 0;
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tmp = __wire_read();
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tmp <<= 8;
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tmp |= __wire_read();
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level = tmp;
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}
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if (level != -1.0) {
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// Print raw value if debug enabled
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#ifdef BH1750_Soft_DEBUG
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Serial.print(F("[BH1750_Soft] Raw value: "));
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Serial.println(level);
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#endif
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if (BH1750_Soft_MTreg != BH1750_Soft_DEFAULT_MTREG) {
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level *= (float)((byte)BH1750_Soft_DEFAULT_MTREG/(float)BH1750_Soft_MTreg);
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// Print MTreg factor if debug enabled
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#ifdef BH1750_Soft_DEBUG
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Serial.print(F("[BH1750_Soft] MTreg factor: "));
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Serial.println( String((float)((byte)BH1750_Soft_DEFAULT_MTREG/(float)BH1750_Soft_MTreg)) );
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#endif
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}
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if (BH1750_Soft_MODE == BH1750_Soft::ONE_TIME_HIGH_RES_MODE_2 || BH1750_Soft_MODE == BH1750_Soft::CONTINUOUS_HIGH_RES_MODE_2) {
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level /= 2;
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}
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// Convert raw value to lux
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level /= BH1750_Soft_CONV_FACTOR;
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// Print converted value if debug enabled
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#ifdef BH1750_Soft_DEBUG
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Serial.print(F("[BH1750_Soft] Converted float value: "));
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Serial.println(level);
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#endif
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}
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return level;
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}
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