1# sensor<a name="EN-US_TOPIC_0000001078202098"></a> 2 3- [Introduction](#section11660541593) 4- [Directory Structure](#section161941989596) 5- [Usage](#section45490312053) 6 - [Available APIs](#section14840627279) 7 - [Usage Guidelines](#section460510231888) 8 9- [Repositories Involved](#section12495154795416) 10 11## Introduction<a name="section11660541593"></a> 12 13The sensor driver module provides and implements sensor-related Hardware Driver Interfaces \(HDIs\), including obtaining sensor information, enabling or disabling a sensor, subscribing to or unsubscribing from sensor data, and setting sensor options. These APIs make service development easier. 14 15**Figure 1** Sensor driver module architecture<a name="fig1292918466322"></a> 16 17 18## Directory Structure<a name="section161941989596"></a> 19 20The directory structure of the sensor driver module is as follows: 21 22``` 23/drivers/peripheral/sensor 24├── hal # HAL code 25│ └── include # HAL header files 26│ └── src # HAL code implementation 27├── interfaces # Driver capability APIs provided for upper-layer services 28│ └── include # APIs exposed externally 29├── test # Test code 30│ └── unittest # Unit test code 31``` 32 33## Usage<a name="section45490312053"></a> 34 35This section uses the acceleration sensor as an example to describe how to use sensor APIs. 36 37### Available APIs<a name="section14840627279"></a> 38 39The HAL module of the sensor driver provides APIs that can be directly called by sensor services to obtain, set, and subscribe to or unsubscribe from sensor data. The following table lists the APIs provided by the sensor driver module. 40 41**Table 1** Major HDIs of the sensor module 42 43<a name="table132511511499"></a> 44<table><thead align="left"><tr id="row22545164911"><th class="cellrowborder" valign="top" width="9.85098509850985%" id="mcps1.2.4.1.1"><p id="p17401913133218"><a name="p17401913133218"></a><a name="p17401913133218"></a>Category</p> 45</th> 46<th class="cellrowborder" valign="top" width="53.88538853885388%" id="mcps1.2.4.1.2"><p id="p20921103144918"><a name="p20921103144918"></a><a name="p20921103144918"></a>API</p> 47</th> 48<th class="cellrowborder" valign="top" width="36.26362636263626%" id="mcps1.2.4.1.3"><p id="p109216317495"><a name="p109216317495"></a><a name="p109216317495"></a>Description</p> 49</th> 50</tr> 51</thead> 52<tbody><tr id="row9256564919"><td class="cellrowborder" valign="top" width="9.85098509850985%" headers="mcps1.2.4.1.1 "><p id="p8437193673211"><a name="p8437193673211"></a><a name="p8437193673211"></a>Query</p> 53</td> 54<td class="cellrowborder" valign="top" width="53.88538853885388%" headers="mcps1.2.4.1.2 "><p id="p11001322173912"><a name="p11001322173912"></a><a name="p11001322173912"></a>int32_t <strong id="b935414557240"><a name="b935414557240"></a><a name="b935414557240"></a>GetAllSensors</strong>(struct SensorInformation **sensorInfo, int32_t *count)</p> 55</td> 56<td class="cellrowborder" valign="top" width="36.26362636263626%" headers="mcps1.2.4.1.3 "><p id="p199227318499"><a name="p199227318499"></a><a name="p199227318499"></a>Obtains information about all sensors in the system. The information about a sensor generally includes the sensor name, sensor vendor, firmware version, hardware version, sensor type ID, sensor ID, maximum measurement range, accuracy, and power.</p> 57</td> 58</tr> 59<tr id="row1026352493"><td class="cellrowborder" rowspan="5" valign="top" width="9.85098509850985%" headers="mcps1.2.4.1.1 "><p id="p06071477324"><a name="p06071477324"></a><a name="p06071477324"></a>Setting</p> 60</td> 61<td class="cellrowborder" valign="top" width="53.88538853885388%" headers="mcps1.2.4.1.2 "><p id="p38874252376"><a name="p38874252376"></a><a name="p38874252376"></a>int32_t <strong id="b199602219271"><a name="b199602219271"></a><a name="b199602219271"></a>Enable</strong>(int32_t sensorId)</p> 62</td> 63<td class="cellrowborder" valign="top" width="36.26362636263626%" headers="mcps1.2.4.1.3 "><p id="p5922331114916"><a name="p5922331114916"></a><a name="p5922331114916"></a>Enables the sensor that has been subscribed to. The subscriber can obtain the sensor data only after the sensor is enabled.</p> 64</td> 65</tr> 66<tr id="row42612518492"><td class="cellrowborder" valign="top" headers="mcps1.2.4.1.1 "><p id="p6923143184914"><a name="p6923143184914"></a><a name="p6923143184914"></a>int32_t <strong id="b84601875330"><a name="b84601875330"></a><a name="b84601875330"></a>Disable</strong>(int32_t sensorId)</p> 67</td> 68<td class="cellrowborder" valign="top" headers="mcps1.2.4.1.2 "><p id="p139231531184912"><a name="p139231531184912"></a><a name="p139231531184912"></a>Disables a sensor.</p> 69</td> 70</tr> 71<tr id="row14261659498"><td class="cellrowborder" valign="top" headers="mcps1.2.4.1.1 "><p id="p992473112496"><a name="p992473112496"></a><a name="p992473112496"></a>int32_t <strong id="b16691194511438"><a name="b16691194511438"></a><a name="b16691194511438"></a>SetBatch</strong>(iint32_t sensorId, int64_t samplingInterval, int64_t reportInterval)</p> 72</td> 73<td class="cellrowborder" valign="top" headers="mcps1.2.4.1.2 "><p id="p14924203134910"><a name="p14924203134910"></a><a name="p14924203134910"></a>Sets the data sampling interval and data reporting interval for the specified sensor.</p> 74</td> 75</tr> 76<tr id="row82615144912"><td class="cellrowborder" valign="top" headers="mcps1.2.4.1.1 "><p id="p170411511281"><a name="p170411511281"></a><a name="p170411511281"></a>int32_t <strong id="b170414153284"><a name="b170414153284"></a><a name="b170414153284"></a>SetMode</strong>(int32_t sensorTypeId, SensorUser *user, int32_t mode)</p> 77</td> 78<td class="cellrowborder" valign="top" headers="mcps1.2.4.1.2 "><p id="p107051159281"><a name="p107051159281"></a><a name="p107051159281"></a>Sets the data reporting mode for the specified sensor.</p> 79</td> 80</tr> 81<tr id="row7260574918"><td class="cellrowborder" valign="top" headers="mcps1.2.4.1.1 "><p id="p492513120494"><a name="p492513120494"></a><a name="p492513120494"></a>int32_t <strong id="b7501191019330"><a name="b7501191019330"></a><a name="b7501191019330"></a>SetOption</strong>(int32_t sensorId, uint32_t option)</p> 82</td> 83<td class="cellrowborder" valign="top" headers="mcps1.2.4.1.2 "><p id="p5926031124914"><a name="p5926031124914"></a><a name="p5926031124914"></a>Sets options for the specified sensor, including its measurement range and accuracy.</p> 84</td> 85</tr> 86<tr id="row5261957493"><td class="cellrowborder" rowspan="2" valign="top" width="9.85098509850985%" headers="mcps1.2.4.1.1 "><p id="p1039815743211"><a name="p1039815743211"></a><a name="p1039815743211"></a>Data subscription and unsubscription</p> 87</td> 88<td class="cellrowborder" valign="top" width="53.88538853885388%" headers="mcps1.2.4.1.2 "><p id="p11530101054411"><a name="p11530101054411"></a><a name="p11530101054411"></a>int32_t <strong id="b0569161217334"><a name="b0569161217334"></a><a name="b0569161217334"></a>Register</strong>(RecordDataCallback cb)</p> 89</td> 90<td class="cellrowborder" valign="top" width="36.26362636263626%" headers="mcps1.2.4.1.3 "><p id="p892633118493"><a name="p892633118493"></a><a name="p892633118493"></a>Registers the callback for reporting sensor data to the subscriber.</p> 91</td> 92</tr> 93<tr id="row10900102644918"><td class="cellrowborder" valign="top" headers="mcps1.2.4.1.1 "><p id="p196491214133110"><a name="p196491214133110"></a><a name="p196491214133110"></a>int32_t <strong id="b13758151483317"><a name="b13758151483317"></a><a name="b13758151483317"></a>Unregister</strong>(void)</p> 94</td> 95<td class="cellrowborder" valign="top" headers="mcps1.2.4.1.2 "><p id="p5817133119"><a name="p5817133119"></a><a name="p5817133119"></a>Unregisters the callback for reporting sensor data.</p> 96</td> 97</tr> 98<tr id="row0353356768"><td class="cellrowborder" rowspan="2" valign="top" width="9.85098509850985%" headers="mcps1.2.4.1.1 "><p id="p6596162112564"><a name="p6596162112564"></a><a name="p6596162112564"></a>Instance creation</p> 99</td> 100<td class="cellrowborder" valign="top" width="53.88538853885388%" headers="mcps1.2.4.1.2 "><p id="p13679191616561"><a name="p13679191616561"></a><a name="p13679191616561"></a>const struct SensorInterface *<strong id="b334310134717"><a name="b334310134717"></a><a name="b334310134717"></a>NewSensorInterfaceInstance</strong>(void)</p> 101</td> 102<td class="cellrowborder" valign="top" width="36.26362636263626%" headers="mcps1.2.4.1.3 "><p id="p19679181612563"><a name="p19679181612563"></a><a name="p19679181612563"></a>Creates a <strong id="b166561232174515"><a name="b166561232174515"></a><a name="b166561232174515"></a>SensorInterface</strong> instance.</p> 103</td> 104</tr> 105<tr id="row53542561265"><td class="cellrowborder" valign="top" headers="mcps1.2.4.1.1 "><p id="p15680111655611"><a name="p15680111655611"></a><a name="p15680111655611"></a>int32_t <strong id="b99024181871"><a name="b99024181871"></a><a name="b99024181871"></a>FreeSensorInterfaceInstance</strong>(void)</p> 106</td> 107<td class="cellrowborder" valign="top" headers="mcps1.2.4.1.2 "><p id="p18680916165620"><a name="p18680916165620"></a><a name="p18680916165620"></a>Releases the <strong id="b1067184719453"><a name="b1067184719453"></a><a name="b1067184719453"></a>SensorInterface</strong> instance.</p> 108</td> 109</tr> 110</tbody> 111</table> 112 113### Usage Guidelines<a name="section460510231888"></a> 114 115Sample code 116 117``` 118#include "sensor_if.h" 119 120/* Create a callback. */ 121void SensorDataCallback(struct SensorEvents *event) 122{ 123 if(event == NULL){ 124 return; 125 } 126 float *sensorData=(float *)event->data; 127 printf("sensor data[%f]", *sensorData); 128} 129 130void SensorSample(void) 131{ 132 int ret; 133 struct SensorInformation *sensorInfo = NULL; 134 int32_t count = 0; 135 int32_t sensorInterval = 200000000; /* Set the data sampling rate to 200000000, in the unit of nanoseconds (200 ms). */ 136 137 /* 1. Create a SensorInterface instance. */ 138 struct SensorInterface *sensorDev = NewSensorInterfaceInstance(); 139 if (sensorDev == NULL) { 140 return; 141 } 142 /* 2. Register a sensor data callback. */ 143 ret = sensorDev->Register(0, SensorDataCallback); 144 if (ret != 0) { 145 return; 146 } 147 /* 3. Obtain the list of sensors supported by the device. */ 148 ret = GetAllSensors(&sensorInfo, &count); 149 if (ret != 0) { 150 return; 151 } 152 /* 4. Set the sensor sampling rate. */ 153 ret = SetBatch(SENSOR_TYPE_ACCELEROMETER, sensorInterval, 0); 154 if (ret != 0) { 155 return; 156 } 157 /* 5. Enable the sensor. */ 158 ret = Enable(SENSOR_TYPE_ACCELEROMETER); 159 if (ret != 0) { 160 return; 161 } 162 /* 6. Disable the sensor. */ 163 ret = Disable(SENSOR_TYPE_ACCELEROMETER); 164 if (ret != 0) { 165 return; 166 } 167 /* 7. Unregister the sensor data callback. */ 168 ret = Unregister(0); 169 if (ret != 0) { 170 return; 171 } 172 /* 8. Release the SensorInterface instance. 173 ret = FreeSensorInterfaceInstance(); 174 if (ret != 0) { 175 return; 176 } 177} 178``` 179 180## Repositories Involved<a name="section12495154795416"></a> 181 182[Driver subsystem](https://gitee.com/openharmony/docs/blob/master/en/readme/driver-subsystem.md) 183 184[drivers\_framework](https://gitee.com/openharmony/drivers_framework/blob/master/README.md) 185 186[drivers\_adapter](https://gitee.com/openharmony/drivers_adapter/blob/master/README.md) 187 188[drivers\_adapter\_khdf\_linux](https://gitee.com/openharmony/drivers_adapter_khdf_linux/blob/master/README.md) 189 190[drivers\_peripheral](https://gitee.com/openharmony/drivers_peripheral) 191 192
