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149 lines
5.0 KiB
149 lines
5.0 KiB
// -----------------------------------------------------------------------------
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// BH1750 Liminosity sensor over I2C
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// Copyright (C) 2017-2019 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 "I2CSensor.h"
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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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static constexpr bool bh1750_is_mode2(unsigned char mode) {
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return (mode == BH1750_CONTINUOUS_HIGH_RES_MODE_2) || (mode == BH1750_ONE_TIME_HIGH_RES_MODE_2);
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}
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class BH1750Sensor : public I2CSensor<> {
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public:
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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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unsigned char getMode() const {
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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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unsigned char id() const override {
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return SENSOR_BH1750_ID;
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}
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unsigned char count() const override {
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return 1;
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}
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// Initialization method, must be idempotent
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void begin() override {
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if (!_dirty) {
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return;
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}
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// I2C auto-discover
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static constexpr uint8_t addresses[] {0x23, 0x5C};
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auto address = findAndLock(addresses);
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if (address == 0) {
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return;
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}
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// Run configuration on next update
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_run_configure = true;
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_ready = true;
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_dirty = false;
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}
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// Descriptive name of the sensor
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String description() const override {
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char buffer[32];
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snprintf_P(buffer, sizeof(buffer),
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PSTR("BH1750 @ I2C (0x%02X)"), lockedAddress());
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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) const override {
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if (index == 0) return MAGNITUDE_LUX;
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return MAGNITUDE_NONE;
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}
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// Pre-read hook (usually to populate registers with up-to-date data)
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void pre() override {
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_error = SENSOR_ERROR_OK;
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_lux = _read(lockedAddress());
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}
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// Current value for slot # index
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double value(unsigned char index) override {
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if (index == 0) return _lux;
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return 0;
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}
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// Number of decimals for a unit (or -1 for default)
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signed char decimals(espurna::sensor::Unit unit) const {
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if (bh1750_is_mode2(_mode)) {
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return 2;
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}
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return 1;
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}
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protected:
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double _read(uint8_t address) {
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// For one-shot modes reconfigure sensor & wait for conversion
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if (_run_configure) {
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// Configure mode
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i2c_write_uint8(address, _mode);
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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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espurna::time::blockingDelay(
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espurna::duration::Milliseconds { (_mode & 0x02) ? 24 : 180 });
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// Keep on running configure each time if one-shot mode
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_run_configure = (_mode & 0x20) > 0;
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}
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uint16_t level = i2c_read_uint16(address);
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if (level == 0xFFFF) {
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_error = SENSOR_ERROR_CRC;
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_run_configure = true;
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return 0;
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}
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// When using HIGH Mode2, value is halved
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const auto multiplier = bh1750_is_mode2(_mode) ? 0.5 : 1.0;
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// TODO also * MTreg?
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return ((double)level / 1.2) * multiplier;
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}
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unsigned char _mode;
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bool _run_configure = false;
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double _lux = 0;
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};
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#endif // SENSOR_SUPPORT && BH1750_SUPPORT
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