sensor.h revision e1c61d3cc8458ce9a15d8109f728e60f5248939d 
1/*
2 * Copyright (C) 2010 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17
18#ifndef ANDROID_SENSOR_H
19#define ANDROID_SENSOR_H
20
21/******************************************************************
22 *
23 * IMPORTANT NOTICE:
24 *
25 *   This file is part of Android's set of stable system headers
26 *   exposed by the Android NDK (Native Development Kit).
27 *
28 *   Third-party source AND binary code relies on the definitions
29 *   here to be FROZEN ON ALL UPCOMING PLATFORM RELEASES.
30 *
31 *   - DO NOT MODIFY ENUMS (EXCEPT IF YOU ADD NEW 32-BIT VALUES)
32 *   - DO NOT MODIFY CONSTANTS OR FUNCTIONAL MACROS
33 *   - DO NOT CHANGE THE SIGNATURE OF FUNCTIONS IN ANY WAY
34 *   - DO NOT CHANGE THE LAYOUT OR SIZE OF STRUCTURES
35 */
36
37/*
38 * Structures and functions to receive and process sensor events in
39 * native code.
40 *
41 */
42
43#include <sys/types.h>
44
45#include <android/looper.h>
46
47#ifdef __cplusplus
48extern "C" {
49#endif
50
51
52/*
53 * Sensor types
54 * (keep in sync with hardware/sensor.h)
55 */
56
57enum {
58    ASENSOR_TYPE_ACCELEROMETER      = 1,
59    ASENSOR_TYPE_MAGNETIC_FIELD     = 2,
60    ASENSOR_TYPE_GYROSCOPE          = 4,
61    ASENSOR_TYPE_LIGHT              = 5,
62    ASENSOR_TYPE_PROXIMITY          = 8
63};
64
65/*
66 * Sensor accuracy measure
67 */
68enum {
69    ASENSOR_STATUS_UNRELIABLE       = 0,
70    ASENSOR_STATUS_ACCURACY_LOW     = 1,
71    ASENSOR_STATUS_ACCURACY_MEDIUM  = 2,
72    ASENSOR_STATUS_ACCURACY_HIGH    = 3
73};
74
75/*
76 * A few useful constants
77 */
78
79/* Earth's gravity in m/s^2 */
80#define ASENSOR_STANDARD_GRAVITY            (9.80665f)
81/* Maximum magnetic field on Earth's surface in uT */
82#define ASENSOR_MAGNETIC_FIELD_EARTH_MAX    (60.0f)
83/* Minimum magnetic field on Earth's surface in uT*/
84#define ASENSOR_MAGNETIC_FIELD_EARTH_MIN    (30.0f)
85
86/*
87 * A sensor event.
88 */
89
90/* NOTE: Must match hardware/sensors.h */
91typedef struct ASensorVector {
92    union {
93        float v[3];
94        struct {
95            float x;
96            float y;
97            float z;
98        };
99        struct {
100            float azimuth;
101            float pitch;
102            float roll;
103        };
104    };
105    int8_t status;
106    uint8_t reserved[3];
107} ASensorVector;
108
109/* NOTE: Must match hardware/sensors.h */
110typedef struct ASensorEvent {
111    int32_t version; /* sizeof(struct ASensorEvent) */
112    int32_t sensor;
113    int32_t type;
114    int32_t reserved0;
115    int64_t timestamp;
116    union {
117        float           data[16];
118        ASensorVector   vector;
119        ASensorVector   acceleration;
120        ASensorVector   magnetic;
121        float           temperature;
122        float           distance;
123        float           light;
124        float           pressure;
125    };
126    int32_t reserved1[4];
127} ASensorEvent;
128
129
130struct ASensorManager;
131typedef struct ASensorManager ASensorManager;
132
133struct ASensorEventQueue;
134typedef struct ASensorEventQueue ASensorEventQueue;
135
136struct ASensor;
137typedef struct ASensor ASensor;
138typedef ASensor const* ASensorRef;
139typedef ASensorRef const* ASensorList;
140
141/*****************************************************************************/
142
143/*
144 * Get a reference to the sensor manager. ASensorManager is a singleton.
145 *
146 * Example:
147 *
148 *     ASensorManager* sensorManager = ASensorManager_getInstance();
149 *
150 */
151ASensorManager* ASensorManager_getInstance();
152
153
154/*
155 * Returns the list of available sensors.
156 */
157int ASensorManager_getSensorList(ASensorManager* manager, ASensorList* list);
158
159/*
160 * Returns the default sensor for the given type, or NULL if no sensor
161 * of that type exist.
162 */
163ASensor const* ASensorManager_getDefaultSensor(ASensorManager* manager, int type);
164
165/*
166 * Creates a new sensor event queue and associate it with a looper.
167 */
168ASensorEventQueue* ASensorManager_createEventQueue(ASensorManager* manager,
169        ALooper* looper, int ident, ALooper_callbackFunc callback, void* data);
170
171/*
172 * Destroys the event queue and free all resources associated to it.
173 */
174int ASensorManager_destroyEventQueue(ASensorManager* manager, ASensorEventQueue* queue);
175
176
177/*****************************************************************************/
178
179/*
180 * Enable the selected sensor. Returns a negative error code on failure.
181 */
182int ASensorEventQueue_enableSensor(ASensorEventQueue* queue, ASensor const* sensor);
183
184/*
185 * Disable the selected sensor. Returns a negative error code on failure.
186 */
187int ASensorEventQueue_disableSensor(ASensorEventQueue* queue, ASensor const* sensor);
188
189/*
190 * Sets the delivery rate of events in microseconds for the given sensor.
191 * Note that this is a hint only, generally event will arrive at a higher
192 * rate. It is an error to set a rate inferior to the value returned by
193 * ASensor_getMinDelay().
194 * Returns a negative error code on failure.
195 */
196int ASensorEventQueue_setEventRate(ASensorEventQueue* queue, ASensor const* sensor, int32_t usec);
197
198/*
199 * Returns true if there are one or more events available in the
200 * sensor queue.  Returns 1 if the queue has events; 0 if
201 * it does not have events; and a negative value if there is an error.
202 */
203int ASensorEventQueue_hasEvents(ASensorEventQueue* queue);
204
205/*
206 * Returns the next available events from the queue.  Returns a negative
207 * value if no events are available or an error has occurred, otherwise
208 * the number of events returned.
209 *
210 * Examples:
211 *   ASensorEvent event;
212 *   ssize_t numEvent = ASensorEventQueue_getEvents(queue, &event, 1);
213 *
214 *   ASensorEvent eventBuffer[8];
215 *   ssize_t numEvent = ASensorEventQueue_getEvents(queue, eventBuffer, 8);
216 *
217 */
218ssize_t ASensorEventQueue_getEvents(ASensorEventQueue* queue,
219                ASensorEvent* events, size_t count);
220
221
222/*****************************************************************************/
223
224/*
225 * Returns this sensor's name (non localized)
226 */
227const char* ASensor_getName(ASensor const* sensor);
228
229/*
230 * Returns this sensor's vendor's name (non localized)
231 */
232const char* ASensor_getVendor(ASensor const* sensor);
233
234/*
235 * Return this sensor's type
236 */
237int ASensor_getType(ASensor const* sensor);
238
239/*
240 * Returns this sensors's resolution
241 */
242float ASensor_getResolution(ASensor const* sensor);
243
244/*
245 * Returns the minimum delay allowed between events in microseconds.
246 * A value of zero means that this sensor doesn't report events at a
247 * constant rate, but rather only when a new data is available.
248 */
249int ASensor_getMinDelay(ASensor const* sensor);
250
251
252#ifdef __cplusplus
253};
254#endif
255
256#endif // ANDROID_SENSOR_H
257