mq3.c
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/*
* Copyright (C) 2014 Freie Universität Berlin
*
* This file is subject to the terms and conditions of the GNU Lesser General
* Public License v2.1. See the file LICENSE in the top level directory for more
* details.
*/
/**
* @ingroup drivers_mq3
* @{
*
* @file
* @brief Device driver implementation for the MQ-3 alcohol sensor
*
* @author Hauke Petersen <hauke.petersen@fu-berlin.de>
*
* @}
*/
#include "mq3.h"
#define PRECISION ADC_RES_10BIT
#define MIN (100U) /* TODO: calibrate to useful value */
#define FACTOR (2.33f) /* TODO: calibrate to useful value */
int mq3_init(mq3_t *dev, adc_t adc_line)
{
dev->adc_line = adc_line;
return adc_init(dev->adc_line);
}
int mq3_read_raw(const mq3_t *dev)
{
return adc_sample(dev->adc_line, PRECISION);
}
int mq3_read(const mq3_t *dev)
{
float res = mq3_read_raw(dev);
res = (res > MIN) ? res - MIN : 0;
return (int)(res * FACTOR);
}