tests: added test for MQ-3 alcohol sensor driver

tests/driver_mq3/Makefile

@@ -0,0 +1,28 @@
+APPLICATION = driver_mq3
+include ../Makefile.tests_common
+
+FEATURES_REQUIRED = periph_adc
+
+# Define default pin mappings for some boards:
+ifneq (,$(filter stm32f4discovery,$(BOARD)))
+  export MQ3_ADC ?= ADC_1
+  export MQ3_CHAN ?= 0
+endif
+
+USEMODULE += mq3
+USEMODULE += vtimer
+
+ifneq (,$(MQ3_ADC))
+  CFLAGS += -DMQ3_ADC=$(MQ3_ADC)
+else
+  # set random default
+  CFLAGS += -DMQ3_ADC=ADC_0
+endif
+ifneq (,$(MQ3_CHAN))
+  CFLAGS += -DMQ3_CHAN=$(MQ3_CHAN)
+else
+  # set random default
+  CFLAGS += -DMQ3_CHAN=0
+endif
+
+include $(RIOTBASE)/Makefile.include

tests/driver_mq3/main.c

@@ -0,0 +1,64 @@
+/*
+ * 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 tests
+ * @{
+ *
+ * @file
+ * @brief       Test application for the MQ-3 alcohol sensor driver
+ *
+ * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
+ *
+ * @}
+ */
+
+#include <stdio.h>
+
+#include "vtimer.h"
+#include "mq3.h"
+#include "periph_conf.h"
+#include "periph/adc.h"
+
+#ifndef MQ3_ADC
+#error "MQ3_ADC is not specified"
+#endif
+#ifndef MQ3_CHAN
+#error "MQ3_CHAN is not specified"
+#endif
+
+int main(void)
+{
+    mq3_t dev;
+    int res;
+
+    puts("MQ-3 alcohol sensor test application\n");
+    printf("Initializing MQ-3 sensor at ADC_%i, channel %i...    ", MQ3_ADC, MQ3_CHAN);
+    res = mq3_init(&dev, MQ3_ADC, MQ3_CHAN);
+    if (res == 0) {
+        puts("[ok]\n");
+    }
+    else {
+        puts("[failed]");
+        return 1;
+    }
+
+    puts("Will now read and print the sensor twice a second:");
+    while (1) {
+        int raw, ppm, alc_a, alc_b;
+        raw = mq3_read_raw(&dev);
+        ppm = mq3_read(&dev);
+        alc_a = ppm / 1000;
+        alc_b = ppm - (alc_a * 1000);
+
+        printf("RAW: %4i, per mille: %1i.%03i\n", raw, alc_a, alc_b);
+
+        vtimer_usleep(500 * 1000);
+    }
+    return 0;
+}