Driver for ultrasonic range meters + example

extras/ultrasonic/ultrasonic.h

@@ -0,0 +1,48 @@
+/*
+ * Driver for ultrasonic range meters, e.g. HC-SR04, HY-SRF05 and so on
+ *
+ * Part of esp-open-rtos
+ * Copyright (C) 2016 Ruslan V. Uss <unclerus@gmail.com>
+ * BSD Licensed as described in the file LICENSE
+ */
+#ifndef EXTRAS_ULTRASONIC_H_
+#define EXTRAS_ULTRASONIC_H_
+
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define ULTRASONIC_ERROR_PING         (-1)
+#define ULTRASONIC_ERROR_PING_TIMEOUT (-2)
+#define ULTRASONIC_ERROR_ECHO_TIMEOUT (-3)
+
+/**
+ * Device descriptor
+ */
+typedef struct
+{
+    uint8_t trigger_pin;
+    uint8_t echo_pin;
+} ultrasonic_sensor_t;
+
+/**
+ * Init ranging module
+ * \param dev Pointer to the device descriptor
+ */
+void ultrasoinc_init(const ultrasonic_sensor_t *dev);
+
+/**
+ * Measure distance
+ * \param dev Pointer to the device descriptor
+ * \param max_distance Maximal distance to measure, centimeters
+ * \return Distance in centimeters or ULTRASONIC_ERROR_xxx if error occured
+ */
+int32_t ultrasoinc_measure_cm(const ultrasonic_sensor_t *dev, uint32_t max_distance);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* EXTRAS_ULTRASONIC_H_ */