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44 lines
1005 B
C
44 lines
1005 B
C
/*
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* Copyright (C) 2014 Freie Universität Berlin
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*
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* This file is subject to the terms and conditions of the GNU Lesser General
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* Public License v2.1. See the file LICENSE in the top level directory for more
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* details.
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*/
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/**
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* @ingroup driver_mq3
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* @{
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*
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* @file
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* @brief Device driver implementation for the MQ-3 alcohol sensor
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*
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* @author Hauke Petersen <hauke.petersen@fu-berlin.de>
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*
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* @}
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*/
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#include "mq3.h"
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#define PRECISION ADC_RES_10BIT
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#define MIN (100U) /* TODO: calibrate to useful value */
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#define FACTOR (2.33f) /* TODO: calibrate to useful value */
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int mq3_init(mq3_t *dev, adc_t adc_line)
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{
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dev->adc_line = adc_line;
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return adc_init(dev->adc_line);
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}
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int mq3_read_raw(const mq3_t *dev)
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{
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return adc_sample(dev->adc_line, PRECISION);
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}
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int mq3_read(const mq3_t *dev)
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{
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float res = mq3_read_raw(dev);
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res = (res > MIN) ? res - MIN : 0;
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return (int)(res * FACTOR);
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}
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