[第二期空气质量分析仪]第2周作业

发布于 2019-09-06 22:40:12 浏览：1240 订阅该版

* 本帖最后由 luckydarcy 于 2019-9-6 23:37 编辑 *

本周出差只能靠晚上零碎的时间学习、做作业。。。

**任务1：温湿度传感器**

**DHT11 温湿度传感器驱动**

驱动部分我们使用了 online package 中的 dht11 软件包，需要开启 menuconfig 选项。
```RT-Thread online packages ---> 
    peripheral libraries and drivers ---> 
        (*) sensors drivers  --->
            (*)   dht11: Digital temperature and humidity sensor(Single bus)  --->```如果没有需要先执行 
```pkgs --upgrade```然后勾选上之后在执行 ```pkgs --update```

**DHT11 温湿度传感器应用线程**dht11 模块采用单总线输出数字信号，DATA 管脚连接到 NUCLEO-F411RE 的 D8 口，查看电路图可知对应的是 MCU 的 PA9。

![NUCLEO-STM32F411部分管脚.png](/uploads/201909/06/222241n9d3zlduq139dhh7.png)

在 application 文件夹下新建 temp_humi_th.c，在该文件中创建温湿度传感器线程，代码如下。

```#include <rtthread.h>
#include <rtdevice.h>
#include "sensor.h"
#include "sensor_dallas_dht11.h"
#include "drv_gpio.h"

/* Modify this pin according to the actual wiring situation */
#define DHT11_DATA_PIN    GET_PIN(A, 9)  /* Arduino D8 */

static void temp_humi_entry(void *parameter)
{
    rt_device_t dev = RT_NULL;
    struct rt_sensor_data sensor_data;
    rt_size_t res;
    rt_uint8_t get_data_freq = 1; /* 1Hz */

dev = rt_device_find("temp_dht11");
    if (dev == RT_NULL)
    {
        return;
    }

if (rt_device_open(dev, RT_DEVICE_FLAG_RDWR) != RT_EOK)
 {
 rt_kprintf("open device failed! ");
 return;
 }

rt_device_control(dev, RT_SENSOR_CTRL_SET_ODR, (void *)(&get_data_freq));

while (1)
    {
        res = rt_device_read(dev, 0, &sensor_data, 1);

if (res != 1)
 {
 rt_kprintf("read data failed! result is %d ", res);
 rt_device_close(dev);
 return;
 }
 else
 {
 if (sensor_data.data.temp >= 0)
 {
 uint8_t temp = (sensor_data.data.temp & 0xffff) >> 0; // get temp
 uint8_t humi = (sensor_data.data.temp & 0xffff0000) >> 16; // get humi
 rt_kprintf("temp:%d, humi:%d " ,temp, humi);
 }
 }

rt_thread_delay(1000);
    }
}

static int temp_humi_init(void)
{
    rt_thread_t dht11_thread;

dht11_thread = rt_thread_create("dht_tem",
                                     temp_humi_entry,
                                     RT_NULL,
                                     1024,
                                     RT_THREAD_PRIORITY_MAX / 2,
                                     20);
    if (dht11_thread != RT_NULL)
    {
        rt_thread_startup(dht11_thread);
    }

return RT_EOK;
}
//INIT_APP_EXPORT(temp_humi_init);

static int rt_hw_dht11_port(void)
{
    struct rt_sensor_config cfg;
    
    cfg.intf.user_data = (void *)DHT11_DATA_PIN;
    rt_hw_dht11_init("dht11", &cfg);

return RT_EOK;
}
INIT_COMPONENT_EXPORT(rt_hw_dht11_port);```

硬件连接如下
![dht11硬件.jpeg](/uploads/201909/06/223042i2fx0eue2035zzh8.jpeg)

执行情况如下
![aht11应用执行.png](/uploads/201909/06/223229rxnt1hgvhn8vguuf.png)

**任务2：PM2.5 粉尘传感器**
GP2Y1014AU粉尘传感器是夏普开发的一款光学灰尘监测传感器模块，在其中间有一个大洞，空气可以自由流过，它里面邻角位置放着红外发光二极管和光电晶体管，红外发光二极管定向发送红外，当空气中有微粒阻碍红外时，红外线发送漫反射，光电晶体管接收到红外，所以信号输出引脚电压会随之发生变化。因此我们需要使用 ADC 采集该电压信号。

**GP2Y1014AU 粉尘传感器驱动**
借助 CubeMX 生成 ADC 工程，在 stm32fxxx_hal_msp.c 文件里 HAL_MspInit 函数中添加 ADC 初始化代码。

**GP2Y1014AU 粉尘传感器应用线程
**

```static void pm25_entry(void *param)
{
 float pm25_value_f;
 int pm25_value_i;
 while (1)
 {
 pm25_value_f = gp2y_read_pm25();
 pm25_value_i = (int)(pm25_value_f);
 rt_kprintf(" **********************PM25********************** "); 
 rt_kprintf("pm25:%d mg/m3 ",pm25_value_i);
 rt_thread_mdelay(1000);
 }
}

static int pm25_init(void)
{
    rt_thread_t pm25_thread;

pm25_thread = rt_thread_create("gp2y_pm2", pm25_entry, RT_NULL,
                                    1024, RT_THREAD_PRIORITY_MAX / 2 - 1, 20);
    if (dht11_thread != RT_NULL) {
        //温湿度初始化
        gp2y_hw_init();
        //创建线程
        rt_thread_startup(pm25_thread);
    }

return RT_EOK;
}
INIT_APP_EXPORT(pm25_init);```

1 个回答

阿基米东 认证专家 2019-09-06

https://github.com/luhuadong

补充 GP2Y1014AU 粉尘传感器驱动：

```
#define LED_GP2Y_PIN       GET_PIN(A, 5)  /* D9 --> PC7 */
#define ADC_DEV_NAME        "adc1"        /* ADC 设备名称 */
#define ADC_DEV_CHANNEL     5             /* ADC 通道 */

int gp2y_hw_init(void)
{
    rt_err_t ret = RT_EOK;
    /* 查找设备 */
    adc_dev = (rt_adc_device_t)rt_device_find(ADC_DEV_NAME);
    if (adc_dev == RT_NULL)
    {
        rt_kprintf("adc sample run failed! can't find %s device!\n", ADC_DEV_NAME);
        return RT_ERROR;
    }
    
    /* 使能设备 */
    ret = rt_adc_enable(adc_dev, ADC_DEV_CHANNEL);
    if(ret != RT_EOK)
    {
        rt_kprintf("adc enable failed!");
        return ret;
    }
    
    rt_pin_mode(LED_GP2Y_PIN, PIN_MODE_OUTPUT);
    led_off(LED_GP2Y_PIN);
    return ret;   
}

float gp2y_read_pm25(void)
{
    rt_err_t err = RT_EOK;

int sampling_time = 280;  //等待LED开启的时间是280μs
    int delta_time = 40;      //整个脉冲持续时间为320μs。因此，我们还需再等待40μs

uint16_t adc_val;
    float dust_val = 0;
    float voltage;

led_on(LED_GP2Y_PIN);
    rt_hw_us_delay(sampling_time);
    
    /* 读取采样值 */
    adc_val = rt_adc_read(adc_dev, ADC_DEV_CHANNEL);
    //rt_kprintf("the ADC value is :%d--", ADCVal);
    rt_hw_us_delay(delta_time);
    led_off(LED_GP2Y_PIN);
    rt_thread_mdelay(9);
    rt_hw_us_delay(680);  //需要脉宽比0.32ms/10ms的PWM信号驱动传感器中的LED
    
    voltage = adc_val * 3.3 / 4096;
    dust_val = (5000 * voltage / 29) - (3000 / 29);
    
    if(0 == dustVal) {
       dustVal = 0; 
    }
    return dustVal;    
}
```