sensor.h revision 1236710bccd8f5870c0281e24a899c3d58f708e6 
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
109typedef struct AMetaDataEvent {
110    int32_t what;
111    int32_t sensor;
112} AMetaDataEvent;
113
114typedef struct AUncalibratedEvent {
115  union {
116    float uncalib[3];
117    struct {
118      float x_uncalib;
119      float y_uncalib;
120      float z_uncalib;
121    };
122  };
123  union {
124    float bias[3];
125    struct {
126      float x_bias;
127      float y_bias;
128      float z_bias;
129    };
130  };
131} AUncalibratedEvent;
132
133/* NOTE: Must match hardware/sensors.h */
134typedef struct ASensorEvent {
135    int32_t version; /* sizeof(struct ASensorEvent) */
136    int32_t sensor;
137    int32_t type;
138    int32_t reserved0;
139    int64_t timestamp;
140    union {
141        union {
142            float           data[16];
143            ASensorVector   vector;
144            ASensorVector   acceleration;
145            ASensorVector   magnetic;
146            float           temperature;
147            float           distance;
148            float           light;
149            float           pressure;
150            float           relative_humidity;
151            AUncalibratedEvent uncalibrated_gyro;
152            AUncalibratedEvent uncalibrated_magnetic;
153            AMetaDataEvent meta_data;
154        };
155        union {
156            uint64_t        data[8];
157            uint64_t        step_counter;
158        } u64;
159    };
160    int32_t reserved1[4];
161} ASensorEvent;
162
163struct ASensorManager;
164typedef struct ASensorManager ASensorManager;
165
166struct ASensorEventQueue;
167typedef struct ASensorEventQueue ASensorEventQueue;
168
169struct ASensor;
170typedef struct ASensor ASensor;
171typedef ASensor const* ASensorRef;
172typedef ASensorRef const* ASensorList;
173
174/*****************************************************************************/
175
176/*
177 * Get a reference to the sensor manager. ASensorManager is a singleton.
178 *
179 * Example:
180 *
181 *     ASensorManager* sensorManager = ASensorManager_getInstance();
182 *
183 */
184ASensorManager* ASensorManager_getInstance();
185
186
187/*
188 * Returns the list of available sensors.
189 */
190int ASensorManager_getSensorList(ASensorManager* manager, ASensorList* list);
191
192/*
193 * Returns the default sensor for the given type, or NULL if no sensor
194 * of that type exist.
195 */
196ASensor const* ASensorManager_getDefaultSensor(ASensorManager* manager, int type);
197
198/*
199 * Creates a new sensor event queue and associate it with a looper.
200 */
201ASensorEventQueue* ASensorManager_createEventQueue(ASensorManager* manager,
202        ALooper* looper, int ident, ALooper_callbackFunc callback, void* data);
203
204/*
205 * Destroys the event queue and free all resources associated to it.
206 */
207int ASensorManager_destroyEventQueue(ASensorManager* manager, ASensorEventQueue* queue);
208
209
210/*****************************************************************************/
211
212/*
213 * Enable the selected sensor. Returns a negative error code on failure.
214 */
215int ASensorEventQueue_enableSensor(ASensorEventQueue* queue, ASensor const* sensor);
216
217/*
218 * Disable the selected sensor. Returns a negative error code on failure.
219 */
220int ASensorEventQueue_disableSensor(ASensorEventQueue* queue, ASensor const* sensor);
221
222/*
223 * Sets the delivery rate of events in microseconds for the given sensor.
224 * Note that this is a hint only, generally event will arrive at a higher
225 * rate. It is an error to set a rate inferior to the value returned by
226 * ASensor_getMinDelay().
227 * Returns a negative error code on failure.
228 */
229int ASensorEventQueue_setEventRate(ASensorEventQueue* queue, ASensor const* sensor, int32_t usec);
230
231/*
232 * Returns true if there are one or more events available in the
233 * sensor queue.  Returns 1 if the queue has events; 0 if
234 * it does not have events; and a negative value if there is an error.
235 */
236int ASensorEventQueue_hasEvents(ASensorEventQueue* queue);
237
238/*
239 * Returns the next available events from the queue.  Returns a negative
240 * value if no events are available or an error has occurred, otherwise
241 * the number of events returned.
242 *
243 * Examples:
244 *   ASensorEvent event;
245 *   ssize_t numEvent = ASensorEventQueue_getEvents(queue, &event, 1);
246 *
247 *   ASensorEvent eventBuffer[8];
248 *   ssize_t numEvent = ASensorEventQueue_getEvents(queue, eventBuffer, 8);
249 *
250 */
251ssize_t ASensorEventQueue_getEvents(ASensorEventQueue* queue,
252                ASensorEvent* events, size_t count);
253
254
255/*****************************************************************************/
256
257/*
258 * Returns this sensor's name (non localized)
259 */
260const char* ASensor_getName(ASensor const* sensor);
261
262/*
263 * Returns this sensor's vendor's name (non localized)
264 */
265const char* ASensor_getVendor(ASensor const* sensor);
266
267/*
268 * Return this sensor's type
269 */
270int ASensor_getType(ASensor const* sensor);
271
272/*
273 * Returns this sensors's resolution
274 */
275float ASensor_getResolution(ASensor const* sensor);
276
277/*
278 * Returns the minimum delay allowed between events in microseconds.
279 * A value of zero means that this sensor doesn't report events at a
280 * constant rate, but rather only when a new data is available.
281 */
282int ASensor_getMinDelay(ASensor const* sensor);
283
284/*
285 * Returns the maximum size of batches for this sensor. Batches will often be
286 * smaller, as the hardware fifo might be used for other sensors.
287 */
288int ASensor_getFifoMaxEventCount(ASensor const* sensor);
289
290/*
291 * Returns the hardware batch fifo size reserved to this sensor.
292 */
293int ASensor_getFifoReservedEventCount(ASensor const* sensor);
294
295/*
296 * Returns this sensor's string type.
297 */
298const char* ASensor_getStringType(ASensor const* sensor);
299
300#ifdef __cplusplus
301};
302#endif
303
304#endif // ANDROID_SENSOR_H
305