Update definition of the heart rate monitor to include confidence
Change-Id: I88a8cddf647f77588a283c16d37f3f99ecda3115
diff --git a/include/hardware/sensors.h b/include/hardware/sensors.h
index ef86a40..418c348 100644
--- a/include/hardware/sensors.h
+++ b/include/hardware/sensors.h
@@ -797,10 +797,17 @@
* trigger-mode: on-change
* wake-up sensor: no
*
- * A sensor of this type returns the current heart rate if activated.
- * The value is returned as a float which represents the heart rate in beats
- * per minute (BPM).
- * When the sensor cannot measure the heart rate, the returned value must be 0.
+ * A sensor of this type returns the current heart rate.
+ * The events contain the current heart rate in beats per minute (BPM) and the
+ * status of the sensor during the measurement. See heart_rate_event_t for more
+ * details.
+ *
+ * Because this sensor is on-change, events must be generated when and only
+ * when heart_rate.bpm or heart_rate.status have changed since the last
+ * event. The event should be generated no faster than every period_ns passed
+ * to setDelay() or to batch(). See the definition of the on-change trigger
+ * mode for more information.
+ *
* sensor_t.requiredPermission must be set to SENSOR_PERMISSION_BODY_SENSORS.
*/
#define SENSOR_TYPE_HEART_RATE (21)
@@ -819,17 +826,15 @@
/** Minimum magnetic field on Earth's surface */
#define MAGNETIC_FIELD_EARTH_MIN (30.0f)
-
/**
- * status of orientation sensor
+ * Possible values of the status field of sensor events.
*/
-
+#define SENSOR_STATUS_NO_CONTACT -1
#define SENSOR_STATUS_UNRELIABLE 0
#define SENSOR_STATUS_ACCURACY_LOW 1
#define SENSOR_STATUS_ACCURACY_MEDIUM 2
#define SENSOR_STATUS_ACCURACY_HIGH 3
-
/**
* sensor event data
*/
@@ -879,6 +884,17 @@
} meta_data_event_t;
/**
+ * Heart rate event data
+ */
+typedef struct {
+ // Heart rate in beats per minute.
+ // Set to 0 when status is SENSOR_STATUS_UNRELIABLE or ..._NO_CONTACT
+ float bpm;
+ // Status of the sensor for this reading. Set to one SENSOR_STATUS_...
+ int8_t status;
+} heart_rate_event_t;
+
+/**
* Union of the various types of sensor data
* that can be returned.
*/
@@ -935,8 +951,8 @@
/* uncalibrated magnetometer values are in micro-Teslas */
uncalibrated_event_t uncalibrated_magnetic;
- /* heart rate in bpm */
- float heart_rate;
+ /* heart rate data containing value in bpm and status */
+ heart_rate_event_t heart_rate;
/* this is a special event. see SENSOR_TYPE_META_DATA above.
* sensors_meta_data_event_t events are all reported with a type of