> 文档中心 > 利用鸿蒙系统实现温湿度传感器的数据读取与显示

利用鸿蒙系统实现温湿度传感器的数据读取与显示

      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。

第一:温湿度传感器基本参数

管脚定义与参考电路

I2C时序特性----支持标准100Hz,高速400KHz

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"#define AHT20_I2C_IDX WIFI_IOT_I2C_IDX_0#define AHT20_STARTUP_TIME     20*1000 // 上电启动时间#define AHT20_CALIBRATION_TIME 40*1000 // 初始化(校准)时间#define AHT20_MEASURE_TIME     75*1000 // 测量时间#define AHT20_DEVICE_ADDR   0x38#define AHT20_READ_ADDR     ((0x38<<1)|0x1)#define AHT20_WRITE_ADDR    ((0x38<<1)|0x0)#define AHT20_CMD_CALIBRATION0xBE // 初始化(校准)命令#define AHT20_CMD_CALIBRATION_ARG0  0x08#define AHT20_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。 **/#define AHT20_CMD_TRIGGER0xAC // 触发测量命令#define AHT20_CMD_TRIGGER_ARG0  0x33#define AHT20_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#define AHT20_CMD_RESET      0xBA // 软复位命令#define AHT20_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 **/#define AHT20_STATUS_BUSY_SHIFT 7// bit[7] Busy indication#define AHT20_STATUS_BUSY_MASK  (0x1<<AHT20_STATUS_BUSY_SHIFT)#define AHT20_STATUS_BUSY(status) ((status & AHT20_STATUS_BUSY_MASK) >> AHT20_STATUS_BUSY_SHIFT)#define AHT20_STATUS_MODE_SHIFT 5// bit[6:5] Mode Status#define AHT20_STATUS_MODE_MASK  (0x3<<AHT20_STATUS_MODE_SHIFT)#define AHT20_STATUS_MODE(status) ((status & AHT20_STATUS_MODE_MASK) >> AHT20_STATUS_MODE_SHIFT)     // bit[4] Reserved#define AHT20_STATUS_CALI_SHIFT 3// bit[3] CAL Enable#define AHT20_STATUS_CALI_MASK  (0x1<<AHT20_STATUS_CALI_SHIFT)#define AHT20_STATUS_CALI(status) ((status & AHT20_STATUS_CALI_MASK) >> AHT20_STATUS_CALI_SHIFT)     // bit[2:0] Reserved#define AHT20_STATUS_RESPONSE_MAX 6#define AHT20_RESOLUTION     (1<<20)  // 2^20#define AHT20_MAX_RETRY 10static uint32_t AHT20_Read(uint8_t* buffer, uint32_t buffLen){    WifiIotI2cData data = { 0 };    data.receiveBuf = buffer;    data.receiveLen = buffLen;    uint32_t retval = I2cRead(AHT20_I2C_IDX, AHT20_READ_ADDR, &data);    if (retval != WIFI_IOT_SUCCESS) { printf("I2cRead() failed, %0X!\n", retval); return retval;    }    return WIFI_IOT_SUCCESS;}static uint32_t AHT20_Write(uint8_t* buffer, uint32_t buffLen){    WifiIotI2cData data = { 0 };    data.sendBuf = buffer;    data.sendLen = buffLen;    uint32_t retval = I2cWrite(AHT20_I2C_IDX, AHT20_WRITE_ADDR, &data);    if (retval != WIFI_IOT_SUCCESS) { printf("I2cWrite(%02X) failed, %0X!\n", buffer[0], retval); return retval;    }    return WIFI_IOT_SUCCESS;}// 发送获取状态命令static uint32_t AHT20_StatusCommand(void){    uint8_t statusCmd[] = { AHT20_CMD_STATUS };    return AHT20_Write(statusCmd, sizeof(statusCmd));}// 发送软复位命令static uint32_t AHT20_ResetCommand(void){    uint8_t resetCmd[] = {AHT20_CMD_RESET};    return AHT20_Write(resetCmd, sizeof(resetCmd));}// 发送初始化校准命令static uint32_t AHT20_CalibrateCommand(void){    uint8_t clibrateCmd[] = {AHT20_CMD_CALIBRATION, AHT20_CMD_CALIBRATION_ARG0, AHT20_CMD_CALIBRATION_ARG1};    return AHT20_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_t AHT20_Calibrate(void){    uint32_t retval = 0;    uint8_t buffer[AHT20_STATUS_RESPONSE_MAX];    memset(&buffer, 0x0, sizeof(buffer));    retval = AHT20_StatusCommand();    if (retval != WIFI_IOT_SUCCESS) { return retval;    }    retval = AHT20_Read(buffer, sizeof(buffer));    if (retval != WIFI_IOT_SUCCESS) { return retval;    }    if (AHT20_STATUS_BUSY(buffer[0]) || !AHT20_STATUS_CALI(buffer[0])) { retval = AHT20_ResetCommand(); if (retval != WIFI_IOT_SUCCESS) {     return retval; } usleep(AHT20_STARTUP_TIME); retval = AHT20_CalibrateCommand(); usleep(AHT20_CALIBRATION_TIME); return retval;    }    return WIFI_IOT_SUCCESS;}// 发送 触发测量 命令,开始测量uint32_t AHT20_StartMeasure(void){    uint8_t triggerCmd[] = {AHT20_CMD_TRIGGER, AHT20_CMD_TRIGGER_ARG0, AHT20_CMD_TRIGGER_ARG1};    return AHT20_Write(triggerCmd, sizeof(triggerCmd));}// 接收测量结果,拼接转换为标准值uint32_t AHT20_GetMeasureResult(float* temp, float* humi){    uint32_t retval = 0, i = 0;    if (temp == NULL || humi == NULL) { return WIFI_IOT_FAILURE;    }    uint8_t buffer[AHT20_STATUS_RESPONSE_MAX];    memset(&buffer, 0x0, sizeof(buffer));    retval = AHT20_Read(buffer, sizeof(buffer));  // recv status command result    if (retval != WIFI_IOT_SUCCESS) { return retval;    }    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 result if (retval != WIFI_IOT_SUCCESS) {     return retval; }    }    if (i >= AHT20_MAX_RETRY) { printf("AHT20 device always busy!\r\n"); return WIFI_IOT_FAILURE;    }    uint32_t humiRaw = buffer[1];    humiRaw = (humiRaw << 8) | buffer[2];    humiRaw = (humiRaw <> 4);    *humi = humiRaw / (float)AHT20_RESOLUTION * 100;    uint32_t tempRaw = 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);    return WIFI_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"void Aht20TestTask(void* arg){    (void) arg;    uint32_t retval = 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) { float temp = 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);    }}void Aht20Test(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);

     具体的操作实现如下视频所示。

【新提醒】【学习打卡】-----利用鸿蒙系统实现对温湿度传感器数据操作 - OpenHarmony论坛 - 电子技术论坛 - 广受欢迎的专业电子论坛! (elecfans.com)icon-default.png?t=M5H6https://bbs.elecfans.com/jishu_2291729_1_1.html