/* * Author: * Copyright (c) 2015 Intel Corporation. * * Permission is hereby granted, free of charge, to any person obtaining * a copy of this software and associated documentation files (the * "Software"), to deal in the Software without restriction, including * without limitation the rights to use, copy, modify, merge, publish, * distribute, sublicense, and/or sell copies of the Software, and to * permit persons to whom the Software is furnished to do so, subject to * the following conditions: * * The above copyright notice and this permission notice shall be * included in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ #include #include #include #include "light.h" light_context light_init(int16_t pin) { light_context dev = (light_context) malloc(sizeof(struct _light_context)); if (dev == NULL) return NULL; /* Init aio pin */ dev->aio = mraa_aio_init(pin); if (dev->aio == NULL) { free(dev); return NULL; } /* Set the ADC ref, scale, and offset defaults */ dev->m_aRef = 5.0; dev->m_scale = 1.0; dev->m_offset = 0.0; return dev; } void light_close(light_context dev) { mraa_aio_close(dev->aio); free(dev); } upm_result_t light_set_aref(const light_context dev, float aref) { dev->m_aRef = aref; return UPM_SUCCESS; } upm_result_t light_set_scale(const light_context dev, float scale) { dev->m_scale = scale; return UPM_SUCCESS; } upm_result_t light_set_offset(const light_context dev, float offset) { dev->m_offset = offset; return UPM_SUCCESS; } float light_get_aref(const light_context dev) { return dev->m_aRef; } float light_get_scale(const light_context dev) { return dev->m_scale; } float light_get_offset(const light_context dev) { return dev->m_offset; } upm_result_t light_get_normalized(const light_context dev, float *value) { *value = mraa_aio_read_float(dev->aio); if (*value < 0) return UPM_ERROR_OPERATION_FAILED; return UPM_SUCCESS; } upm_result_t light_get_raw_volts(const light_context dev, float *value) { *value = mraa_aio_read_float(dev->aio); if (*value < 0) return UPM_ERROR_OPERATION_FAILED; /* Scale by the ADC reference voltage */ *value *= dev->m_aRef; return UPM_SUCCESS; } upm_result_t light_get_lux(const light_context dev, float *value) { *value = mraa_aio_read(dev->aio); if (*value < 0) return UPM_ERROR_OPERATION_FAILED; /* Get max adc value range 1023, 2047, 4095, etc... */ float max_adc = (1 << mraa_aio_get_bit(dev->aio)) - 1; /* Convert the value to lux */ *value = 10000.0/pow(((max_adc - *value) * 10.0 / *value)*15.0,4.0/3.0); /* Apply scale */ *value *= dev->m_scale; /* Apply the offset in lux */ *value += dev->m_offset; return UPM_SUCCESS; }