【学习打卡】-----利用鸿蒙系统实现对温湿度传感器数据操作

今天主要和大家聊一聊，如何使用鸿蒙系统去提取AHT20的温湿度传感器的数值，该传感器采用ADC位数为20Bit，具有体积小，精度高和成本低的优点。

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第一：温湿度传感器基本参数

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管脚定义与参考电路

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I2C时序特性----支持标准100Hz，高速400KHz

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第二：温度代码具体实现

                     

                      
                      
                       
                     
上面分析了，温湿度传感器的基本实现原理与方法，主要精力可以放在代码的具体实现上。

                     

                      
                      
                       
                     
#include"aht20.h"#include#include#include#include"wifiiot_i2c.h"#include"wifiiot_errno.h"#defineAHT20_I2C_IDX WIFI_IOT_I2C_IDX_0#defineAHT20_STARTUP_TIME 20*1000// 上电启动时间#defineAHT20_CALIBRATION_TIME 40*1000// 初始化（校准）时间#defineAHT20_MEASURE_TIME 75*1000// 测量时间#defineAHT20_DEVICE_ADDR 0x38#defineAHT20_READ_ADDR ((0x38<<1)|0x1)#defineAHT20_WRITE_ADDR ((0x38<<1)|0x0)#defineAHT20_CMD_CALIBRATION 0xBE// 初始化（校准）命令#defineAHT20_CMD_CALIBRATION_ARG0 0x08#defineAHT20_CMD_CALIBRATION_ARG1 0x00/** * 传感器在采集时需要时间,主机发出测量指令（0xAC）后，延时75毫秒以上再读取转换后的数据并判断返回的状态位是否正常。 * 若状态比特位[Bit7]为0代表数据可正常读取，为1时传感器为忙状态，主机需要等待数据处理完成。 **/#defineAHT20_CMD_TRIGGER 0xAC// 触发测量命令#defineAHT20_CMD_TRIGGER_ARG0 0x33#defineAHT20_CMD_TRIGGER_ARG1 0x00// 用于在无需关闭和再次打开电源的情况下，重新启动传感器系统，软复位所需时间不超过20 毫秒#defineAHT20_CMD_RESET 0xBA// 软复位命令#defineAHT20_CMD_STATUS 0x71// 获取状态命令/** * STATUS 命令回复： * 1. 初始化后触发测量之前，STATUS 只回复 1B 状态值； * 2. 触发测量之后，STATUS 回复6B：1B 状态值 + 2B 湿度 + 4b湿度 + 4b温度 + 2B 温度 * RH = Srh / 2^20 * 100% * T = St / 2^20 * 200 - 50 **/#defineAHT20_STATUS_BUSY_SHIFT 7// bit[7] Busy indication#defineAHT20_STATUS_BUSY_MASK (0x1<#defineAHT20_STATUS_BUSY(status) ((status & AHT20_STATUS_BUSY_MASK) >> AHT20_STATUS_BUSY_SHIFT)#defineAHT20_STATUS_MODE_SHIFT 5// bit[6:5] Mode Status#defineAHT20_STATUS_MODE_MASK (0x3<#defineAHT20_STATUS_MODE(status) ((status & AHT20_STATUS_MODE_MASK) >> AHT20_STATUS_MODE_SHIFT)// bit[4] Reserved#defineAHT20_STATUS_CALI_SHIFT 3// bit[3] CAL Enable#defineAHT20_STATUS_CALI_MASK (0x1<#defineAHT20_STATUS_CALI(status) ((status & AHT20_STATUS_CALI_MASK) >> AHT20_STATUS_CALI_SHIFT)// bit[2:0] Reserved#defineAHT20_STATUS_RESPONSE_MAX 6#defineAHT20_RESOLUTION (1<<20)// 2^20#defineAHT20_MAX_RETRY 10staticuint32_tAHT20_Read(uint8_t* buffer,uint32_tbuffLen){ WifiIotI2cData data = {0}; data.receiveBuf = buffer; data.receiveLen = buffLen;uint32_tretval =I2cRead(AHT20_I2C_IDX, AHT20_READ_ADDR, &data);if(retval != WIFI_IOT_SUCCESS) {printf("I2cRead() failed, %0X!\n", retval);returnretval; }returnWIFI_IOT_SUCCESS; }staticuint32_tAHT20_Write(uint8_t* buffer,uint32_tbuffLen){ WifiIotI2cData data = {0}; data.sendBuf = buffer; data.sendLen = buffLen;uint32_tretval =I2cWrite(AHT20_I2C_IDX, AHT20_WRITE_ADDR, &data);if(retval != WIFI_IOT_SUCCESS) {printf("I2cWrite(%02X) failed, %0X!\n", buffer[0], retval);returnretval; }returnWIFI_IOT_SUCCESS; }// 发送获取状态命令staticuint32_tAHT20_StatusCommand(void){uint8_tstatusCmd[] = { AHT20_CMD_STATUS };returnAHT20_Write(statusCmd,sizeof(statusCmd)); }// 发送软复位命令staticuint32_tAHT20_ResetCommand(void){uint8_tresetCmd[] = {AHT20_CMD_RESET};returnAHT20_Write(resetCmd,sizeof(resetCmd)); }// 发送初始化校准命令staticuint32_tAHT20_CalibrateCommand(void){uint8_tclibrateCmd[] = {AHT20_CMD_CALIBRATION, AHT20_CMD_CALIBRATION_ARG0, AHT20_CMD_CALIBRATION_ARG1};returnAHT20_Write(clibrateCmd,sizeof(clibrateCmd)); }// 读取温湿度值之前， 首先要看状态字的校准使能位Bit[3]是否为 1(通过发送0x71可以获取一个字节的状态字)，// 如果不为1，要发送0xBE命令(初始化)，此命令参数有两个字节， 第一个字节为0x08，第二个字节为0x00。uint32_tAHT20_Calibrate(void){uint32_tretval =0;uint8_tbuffer[AHT20_STATUS_RESPONSE_MAX];memset(&buffer,0x0,sizeof(buffer)); retval =AHT20_StatusCommand();if(retval != WIFI_IOT_SUCCESS) {returnretval; } retval =AHT20_Read(buffer,sizeof(buffer));if(retval != WIFI_IOT_SUCCESS) {returnretval; }if(AHT20_STATUS_BUSY(buffer[0]) || !AHT20_STATUS_CALI(buffer[0])) { retval =AHT20_ResetCommand();if(retval != WIFI_IOT_SUCCESS) {returnretval; }usleep(AHT20_STARTUP_TIME); retval =AHT20_CalibrateCommand();usleep(AHT20_CALIBRATION_TIME);returnretval; }returnWIFI_IOT_SUCCESS; }// 发送 触发测量 命令，开始测量uint32_tAHT20_StartMeasure(void){uint8_ttriggerCmd[] = {AHT20_CMD_TRIGGER, AHT20_CMD_TRIGGER_ARG0, AHT20_CMD_TRIGGER_ARG1};returnAHT20_Write(triggerCmd,sizeof(triggerCmd)); }// 接收测量结果，拼接转换为标准值uint32_tAHT20_GetMeasureResult(float* temp,float* humi){uint32_tretval =0, i =0;if(temp ==NULL|| humi ==NULL) {returnWIFI_IOT_FAILURE; }uint8_tbuffer[AHT20_STATUS_RESPONSE_MAX];memset(&buffer,0x0,sizeof(buffer)); retval =AHT20_Read(buffer,sizeof(buffer));// recv status command resultif(retval != WIFI_IOT_SUCCESS) {returnretval; }for(i =0;AHT20_STATUS_BUSY(buffer[0]) && i < AHT20_MAX_RETRY; i++) {// printf("AHT20 device busy, retry %d/%d!\r\n", i, AHT20_MAX_RETRY);usleep(AHT20_MEASURE_TIME); retval =AHT20_Read(buffer,sizeof(buffer));// recv status command resultif(retval != WIFI_IOT_SUCCESS) {returnretval; } }if(i >= AHT20_MAX_RETRY) {printf("AHT20 device always busy!\r\n");returnWIFI_IOT_FAILURE; }uint32_thumiRaw = buffer[1]; humiRaw = (humiRaw <<8) | buffer[2]; humiRaw = (humiRaw <<4) | ((buffer[3] &0xF0) >>4); *humi = humiRaw / (float)AHT20_RESOLUTION *100;uint32_ttempRaw = buffer[3] &0x0F; tempRaw = (tempRaw <<8) | buffer[4]; tempRaw = (tempRaw <<8) | buffer[5]; *temp = tempRaw / (float)AHT20_RESOLUTION *200-50;// printf("humi = %05X, %f, temp= %05X, %f\r\n", humiRaw, *humi, tempRaw, *temp);returnWIFI_IOT_SUCCESS; }

接下来，可以利用鸿蒙系统对温湿度传感器里面的温度数据进行读取，然后再将获取到的温湿度数据进行显示输出。

                     

                      
                      
                       
                     
#include"aht20.h"#include#include#include"ohos_init.h"#include"cmsis_os2.h"#include"wifiiot_gpio.h"#include"wifiiot_gpio_ex.h"#include"wifiiot_i2c.h"voidAht20TestTask(void* arg){ (void) arg;uint32_tretval =0;IoSetFunc(WIFI_IOT_IO_NAME_GPIO_13, WIFI_IOT_IO_FUNC_GPIO_13_I2C0_SDA);IoSetFunc(WIFI_IOT_IO_NAME_GPIO_14, WIFI_IOT_IO_FUNC_GPIO_14_I2C0_SCL);I2cInit(WIFI_IOT_I2C_IDX_0,400*1000); retval =AHT20_Calibrate();printf("AHT20_Calibrate: %d\r\n", retval);while(1) {floattemp =0.0, humi =0.0; retval =AHT20_StartMeasure();printf("AHT20_StartMeasure: %d\r\n", retval); retval =AHT20_GetMeasureResult(&temp, &humi);printf("AHT20_GetMeasureResult: %d, temp = %.2f, humi = %.2f\r\n", retval, temp, humi);sleep(1); } }voidAht20Test(void){ osThreadAttr_t attr; attr.name ="Aht20Task"; attr.attr_bits =0U; attr.cb_mem =NULL; attr.cb_size =0U; attr.stack_mem =NULL; attr.stack_size =4096; attr.priority = osPriorityNormal;if(osThreadNew(Aht20TestTask,NULL, &attr) ==NULL) {printf("[Aht20Test] Failed to create Aht20TestTask!\n"); } }APP_FEATURE_INIT(Aht20Test);

                     

                      
                      
                       
                     
具体的操作实现如视频所示。

第三：视频显示效果