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155 lines
5.2 KiB
155 lines
5.2 KiB
// -----------------------------------------------------------------------------
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// BH1750 Liminosity sensor over I2C
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// Copyright (C) 2017 by Xose Pérez <xose dot perez at gmail dot com>
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// -----------------------------------------------------------------------------
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#if SENSOR_SUPPORT && BH1750_SUPPORT
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#pragma once
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#include "Arduino.h"
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#include "I2CSensor.h"
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#if I2C_USE_BRZO
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#include <brzo_i2c.h>
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#else
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#include <Wire.h>
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#endif
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#define BH1750_CONTINUOUS_HIGH_RES_MODE 0x10 // Start measurement at 1lx resolution. Measurement time is approx 120ms.
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#define BH1750_CONTINUOUS_HIGH_RES_MODE_2 0x11 // Start measurement at 0.5lx resolution. Measurement time is approx 120ms.
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#define BH1750_CONTINUOUS_LOW_RES_MODE 0x13 // Start measurement at 4lx resolution. Measurement time is approx 16ms.
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#define BH1750_ONE_TIME_HIGH_RES_MODE 0x20 // Start measurement at 1lx resolution. Measurement time is approx 120ms.
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// Device is automatically set to Power Down after measurement.
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#define BH1750_ONE_TIME_HIGH_RES_MODE_2 0x21 // Start measurement at 0.5lx resolution. Measurement time is approx 120ms.
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// Device is automatically set to Power Down after measurement.
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#define BH1750_ONE_TIME_LOW_RES_MODE 0x23 // Start measurement at 1lx resolution. Measurement time is approx 120ms.
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// Device is automatically set to Power Down after measurement.
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class BH1750Sensor : public I2CSensor {
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public:
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// ---------------------------------------------------------------------
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// Public
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// ---------------------------------------------------------------------
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BH1750Sensor(): I2CSensor() {
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_sensor_id = SENSOR_BH1750_ID;
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_count = 1;
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}
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// ---------------------------------------------------------------------
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void setMode(unsigned char mode) {
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if (_mode == mode) return;
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_mode = mode;
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_dirty = true;
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}
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// ---------------------------------------------------------------------
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unsigned char getMode() {
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return _mode;
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}
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// ---------------------------------------------------------------------
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// Sensor API
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// ---------------------------------------------------------------------
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// Initialization method, must be idempotent
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void begin() {
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if (!_dirty) return;
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_dirty = false;
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// I2C auto-discover
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unsigned char addresses[] = {0x23, 0x5C};
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_address = _begin_i2c(_address, sizeof(addresses), addresses);
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if (_address == 0) return;
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// Configure
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_configure();
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delay(10);
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}
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// Descriptive name of the sensor
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String description() {
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char buffer[25];
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snprintf(buffer, sizeof(buffer), "BH1750 @ I2C (0x%02X)", _address);
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return String(buffer);
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}
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// Type for slot # index
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unsigned char type(unsigned char index) {
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_error = SENSOR_ERROR_OK;
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if (index == 0) return MAGNITUDE_LUX;
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_error = SENSOR_ERROR_OUT_OF_RANGE;
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return MAGNITUDE_NONE;
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}
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// Current value for slot # index
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double value(unsigned char index) {
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_error = SENSOR_ERROR_OK;
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if (index == 0) return _read();
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_error = SENSOR_ERROR_OUT_OF_RANGE;
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return 0;
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}
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protected:
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void _configure() {
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#if I2C_USE_BRZO
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uint8_t buffer[1] = {_mode};
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brzo_i2c_start_transaction(_address, I2C_SCL_FREQUENCY);
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brzo_i2c_write(buffer, 1, false);
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brzo_i2c_end_transaction();
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#else
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Wire.beginTransmission(_address);
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Wire.write(_mode);
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Wire.endTransmission();
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#endif
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}
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double _read() {
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double level;
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uint8_t buffer[2];
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// For one-shot modes reconfigure sensor & wait for conversion
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if (_mode & 0x20) {
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_configure();
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// According to datasheet
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// conversion time is ~16ms for low resolution
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// and ~120 for high resolution
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// but more time is needed
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unsigned long wait = (_mode & 0x02) ? 24 : 180;
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unsigned long start = millis();
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while (millis() - start < wait) delay(1);
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}
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#if I2C_USE_BRZO
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brzo_i2c_start_transaction(_address, I2C_SCL_FREQUENCY);
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brzo_i2c_read(buffer, 2, false);
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brzo_i2c_end_transaction();
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#else
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Wire.beginTransmission(_address);
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Wire.requestFrom(_address, (unsigned char) 2);
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buffer[0] = Wire.read();
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buffer[1] = Wire.read();
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Wire.endTransmission();
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#endif
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level = buffer[0] * 256 + buffer[1];
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return level / 1.2;
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}
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unsigned char _mode;
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};
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#endif // SENSOR_SUPPORT && SI7021_SUPPORT
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