sensor.h revision 7438fd1a0132bc6de101e2a5f75040a119b6f29b 
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        float           step_counter;
126    };
127    int32_t reserved1[4];
128} ASensorEvent;
129
130
131struct ASensorManager;
132typedef struct ASensorManager ASensorManager;
133
134struct ASensorEventQueue;
135typedef struct ASensorEventQueue ASensorEventQueue;
136
137struct ASensor;
138typedef struct ASensor ASensor;
139typedef ASensor const* ASensorRef;
140typedef ASensorRef const* ASensorList;
141
142/*****************************************************************************/
143
144/*
145 * Get a reference to the sensor manager. ASensorManager is a singleton.
146 *
147 * Example:
148 *
149 *     ASensorManager* sensorManager = ASensorManager_getInstance();
150 *
151 */
152ASensorManager* ASensorManager_getInstance();
153
154
155/*
156 * Returns the list of available sensors.
157 */
158int ASensorManager_getSensorList(ASensorManager* manager, ASensorList* list);
159
160/*
161 * Returns the default sensor for the given type, or NULL if no sensor
162 * of that type exist.
163 */
164ASensor const* ASensorManager_getDefaultSensor(ASensorManager* manager, int type);
165
166/*
167 * Creates a new sensor event queue and associate it with a looper.
168 */
169ASensorEventQueue* ASensorManager_createEventQueue(ASensorManager* manager,
170        ALooper* looper, int ident, ALooper_callbackFunc callback, void* data);
171
172/*
173 * Destroys the event queue and free all resources associated to it.
174 */
175int ASensorManager_destroyEventQueue(ASensorManager* manager, ASensorEventQueue* queue);
176
177
178/*****************************************************************************/
179
180/*
181 * Enable the selected sensor. Returns a negative error code on failure.
182 */
183int ASensorEventQueue_enableSensor(ASensorEventQueue* queue, ASensor const* sensor);
184
185/*
186 * Disable the selected sensor. Returns a negative error code on failure.
187 */
188int ASensorEventQueue_disableSensor(ASensorEventQueue* queue, ASensor const* sensor);
189
190/*
191 * Sets the delivery rate of events in microseconds for the given sensor.
192 * Note that this is a hint only, generally event will arrive at a higher
193 * rate. It is an error to set a rate inferior to the value returned by
194 * ASensor_getMinDelay().
195 * Returns a negative error code on failure.
196 */
197int ASensorEventQueue_setEventRate(ASensorEventQueue* queue, ASensor const* sensor, int32_t usec);
198
199/*
200 * Returns true if there are one or more events available in the
201 * sensor queue.  Returns 1 if the queue has events; 0 if
202 * it does not have events; and a negative value if there is an error.
203 */
204int ASensorEventQueue_hasEvents(ASensorEventQueue* queue);
205
206/*
207 * Returns the next available events from the queue.  Returns a negative
208 * value if no events are available or an error has occurred, otherwise
209 * the number of events returned.
210 *
211 * Examples:
212 *   ASensorEvent event;
213 *   ssize_t numEvent = ASensorEventQueue_getEvents(queue, &event, 1);
214 *
215 *   ASensorEvent eventBuffer[8];
216 *   ssize_t numEvent = ASensorEventQueue_getEvents(queue, eventBuffer, 8);
217 *
218 */
219ssize_t ASensorEventQueue_getEvents(ASensorEventQueue* queue,
220                ASensorEvent* events, size_t count);
221
222
223/*****************************************************************************/
224
225/*
226 * Returns this sensor's name (non localized)
227 */
228const char* ASensor_getName(ASensor const* sensor);
229
230/*
231 * Returns this sensor's vendor's name (non localized)
232 */
233const char* ASensor_getVendor(ASensor const* sensor);
234
235/*
236 * Return this sensor's type
237 */
238int ASensor_getType(ASensor const* sensor);
239
240/*
241 * Returns this sensors's resolution
242 */
243float ASensor_getResolution(ASensor const* sensor);
244
245/*
246 * Returns the minimum delay allowed between events in microseconds.
247 * A value of zero means that this sensor doesn't report events at a
248 * constant rate, but rather only when a new data is available.
249 */
250int ASensor_getMinDelay(ASensor const* sensor);
251
252
253#ifdef __cplusplus
254};
255#endif
256
257#endif // ANDROID_SENSOR_H
258