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基于RT-Thread+RA6M4的环境采集系统

发布于 2022-07-17 19:20:35 浏览：560 订阅该版

[tocm]

[202207172031.mp4](https://club.rt-thread.org/file_download/be71cb6068a5c20a)很高兴能参加此次活动 https://club.rt-thread.org/ask/article/a07e2bf367df1195.html

瑞萨这款M4开发板功能比较强悍，官方支持也比较友好
https://gitee.com/rtthread/rt-thread/tree/gitee_master/bsp/renesas

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20220717/10b7c6edf2f91c58c9b95ab3ee6d72de.png)
官方已支持uart iic(软件模拟) gpio 等功能，并且通过两次直播也进行了外设使用的介绍

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20220717/fa1cd9a894a51f770879b92db1de1f0f.png)
# 概要设计
本次主要基于此开发板完成温度、湿度、甲醛浓度的环境量采集功能，并通过iic 的OLED 12864进行显示，整体实现框图如下

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20220717/cd7bcc6fd630e62e5544e73a268b1f89.png)
# 详细设计
## oled显示部分
  环境搭建参考https://blog.csdn.net/vor234/article/details/125634313
  软件包添加u8g2
![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20220717/2db0320a80d8a8d7d118939feb66ea77.png)
u8g2设置
![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20220717/86fe02a01e1c53ad7bd25227941b9759.png)
开启iic 软件模拟

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20220717/1802cc46aa732550cc2e1c5a6ef5a55c.png)
线程初始化过程
```c
    rt_err_t ret = RT_EOK;
    // Initialization
    u8g2_Setup_ssd1306_i2c_128x64_noname_f( &u8g2, U8G2_R0, u8x8_byte_rtthread_hw_i2c, u8x8_gpio_and_delay_rtthread);
    u8g2_InitDisplay(&u8g2);
    u8g2_SetPowerSave(&u8g2, 0);

rt_thread_t thread = rt_thread_create("ssd1306_u8g2", ssd1306_entry, RT_NULL, 1024, 14, 14);
    if (thread != RT_NULL)
    {
        rt_thread_startup(thread);
    }
    else
    {
        ret = RT_ERROR;
    }
    return ret;```
entry 部分
```c
static void ssd1306_entry(void* params)
{
    while(1)
    {
        u8g2_ClearBuffer(&u8g2);
        u8g2_SetFont(&u8g2, u8g2_font_wqy12_t_gb2312a);
        u8g2_DrawUTF8(&u8g2, 24, 12, "RA6M4环境采集");
        u8g2_DrawUTF8Line(&u8g2, 0, 20, 1, "----------------------------", 0, 0);
        snprintf(datatmp, sizeof(datatmp) - 1, "甲醛: %fmg/m^3", CHO_Data);
        u8g2_DrawUTF8(&u8g2, 4, 32, datatmp);
        snprintf(datatmp,sizeof(datatmp)-1,"温度:%d.%d 摄氏度",temp_data.data.temp/10,temp_data.data.temp%10);
        u8g2_DrawUTF8(&u8g2, 4, 44, datatmp);
        snprintf(datatmp,sizeof(datatmp)-1,"湿度:%d%%",humi_data.data.humi/10);
        u8g2_DrawUTF8(&u8g2, 4, 56, datatmp);
        u8g2_SendBuffer(&u8g2);
        //rt_hw_us_delay(500000);
        rt_thread_delay(rt_tick_from_millisecond(500));
    }

}```
此线程使用全局变量，500ms 刷新界面显示，并设置中文显示字体及大小，注意此文件要以utf8格式编码保存，不然显示屏字会乱码或不显示

## dht11 部分
### 管脚指定
dht11 采用p102 管脚，管脚定义的内核值计算在bsp_io.h文件中有定义，可做参考。
针对此cpk 板子在bsp_pin_cfg.h也有相应的宏定义，方便进行查找，不用找原理图了 ，嘻嘻，
![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20220717/39da771f58b88fc17b6dc1573a1f1967.png)

取消库里hw delay的实现，也可添加drv_comm 进行systick 引用
fsp 将相应管脚打开，如下图，不打开将无法检测到温度 湿度信息

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20220717/9b7a3bbb7f1f5491da6a31e105ce180e.png)
线程初始化
```c
static int dht11_thread(void)
{

humi_dev = rt_device_find("humi_dht");
    if(!humi_dev)
    {
        rt_kprintf("can not find humi device\n");
        return -1;
    }

if (rt_device_open(humi_dev, RT_DEVICE_FLAG_RDWR))
    {
        rt_kprintf("Open humi device failed.\n");
        return -1;
    }

temp_dev  = rt_device_find("temp_dht");
    if (!temp_dev)
    {
        rt_kprintf("Can't find temp device.\n");
        return -1 ;
    }

if (rt_device_open(temp_dev, RT_DEVICE_FLAG_RDWR))
    {
        rt_kprintf("Open temp device failed.\n");
        return -1;
    }

rt_thread_t dht11_thread;
    dht11_thread = rt_thread_create("dht11_thread", dht11_entry, RT_NULL, 1024, 14, 20);
    if(dht11_thread)
    {
        rt_thread_startup(dht11_thread);
    }
}
```
entry 部分
通过rt_device_read 读取 传感器数据，并存入到rt_sensor_data 中，方便oled进行数据显示
```c
static void dht11_entry(void* params)
{
    while(1)
    {
        if (1 != rt_device_read(humi_dev, 0, &humi_data, 1))
        {
            rt_kprintf("Read humi data failed.\n");
        }
        else
        {
            //rt_kprintf("[%d] Humi: %d\n", humi_data.timestamp, humi_data.data.humi);
        }
        if (1 != rt_device_read(temp_dev, 0, &temp_data, 1))
        {
            rt_kprintf("Read temp data failed.\n");
        }
        else
        {
            //rt_kprintf("[%d] Temp: %d\n", temp_data.timestamp, temp_data.data.temp);
        }

rt_thread_mdelay(3000);
    }

}
```
## 甲醛模块实现
 
![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20220717/3d556e822f3b14567a86b35639692511.png.webp)

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20220717/7e832e28673b75202aa20ac548dccc4e.png.webp)
管脚定义

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20220717/7510af4386b7d8949416876fc89ab389.png.webp)
串口通信格式

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20220717/99cd73652fce8697c68a1f1f842e99c6.png)

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20220717/691c97b8308da1c23b35e316073c706e.png.webp)
注意事项

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20220717/e78ab17e75a1379d18718e4db62e337b.png.webp)
数据计算过程

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20220717/8d3bf55d6e6f517f224d2d5a8e911172.png)
Byte5 +Byte4*256=ppb

ppm=ppb/1000

ppm与浓度转换关系为

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20220717/43aadaf20c24dbb1165e5be3de9d0d1f.png)
由https://baike.baidu.com/item/%E7%94%B2%E9%86%9B/167033?fr=kg_qa#reference-[2]-4913-wrap 百科可知甲醛分子量为30.3

则 质量浓度= ppm*30.3/22.4

空气含量标准

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20220717/219d49fe87d4ad70c29d926d1d3c94f2.png.webp)

实现过程
fsp 开启uart1

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20220717/b69620cff0225f7718332f1e55b7bc3c.png.webp)
rt-thread setting 中开启uart1
线程创建过程
```c
static int uart_CH0_thread(void)
{
    rt_err_t ret = RT_EOK;
    char uart_name[RT_NAME_MAX];
    rt_strncpy(uart_name, CHO_UART_NAME, RT_NAME_MAX);
    /* 查找串口设备 */
    serial = rt_device_find(uart_name);
    if (!serial)
    {
        rt_kprintf("find %s failed!\n", uart_name);
        return RT_ERROR;
    }
      rt_sem_init(&rx_sem, "rx_sem", 0, RT_IPC_FLAG_FIFO);
      rt_device_open(serial, RT_DEVICE_OFLAG_RDWR | RT_DEVICE_FLAG_INT_RX);
      rt_device_set_rx_indicate(serial, uart_in);
      rt_thread_t thread = rt_thread_create("serial_cho", uart_CHO_thread_entry, RT_NULL, 1024, 25, 9);
      if (thread != RT_NULL)
      {
          rt_thread_startup(thread);
      }
      else
      {
          ret = RT_ERROR;
      }
      return ret;

}
```
协议解析过程  并将解析完成数据放到CHO_Data 中，方便oled 动态刷新显示
```
static void uart_CHO_thread_entry(void* parameter)
{
    uint8_t data;
    uint8_t state = 0;
    uint32_t dataH,dataL;
    float tmpdata =0.0;
    char cho_data[40];
    while(1)
    {
        while (rt_device_read(serial, -1, &data, 1) != 1)
        {
            /* 阻塞等待接收信号量，等到信号量后再次读取数据 */
            rt_sem_take(&rx_sem, RT_WAITING_FOREVER);
        }
        switch(state)
        {
        case HeadByte:
            state = data==0xff?NameByte:HeadByte;
            break;
        case NameByte:
            state = data==0x17?UintByte:HeadByte;
            break;
        case  UintByte:
            state = data==0x04?MinByte:HeadByte;
            break;
        case MinByte:
            state = data==0x00?DataHByte:HeadByte;
            break;
        case DataHByte:
            dataH = data;
            state = DataLByte;
            break;
        case DataLByte:
            dataL = data;
            state = FullHByte;
            break;
        case FullHByte:
            state = data==0x13?FullLByte:HeadByte;
            break;
        case FullLByte:
            state = data==0x88?CRCByte:HeadByte;
            break;
        case CRCByte:
            if((data+0x17+0x04+dataH+dataL+0x13+0x88)%256==0)
            {
                tmpdata = (float)(dataH*256+dataL)*0.001f;
                CHO_Data = tmpdata*1.352678571428f;
                //snprintf(cho_data, sizeof(cho_data) - 1, "CH0：%fmg/m^3", CHO_Data);
                //rt_kprintf(" %s\n",cho_data);

}
            state =0;
            break;
        default:
            state =0;
            break;
        }
    }
}```
最终实现效果

![screenshot_af2c6b2ab84e51e96c78560d566b8d6.jpg](https://oss-club.rt-thread.org/uploads/20220717/b8748f30e5414832289b425e4aa007dd.jpg.webp)

开源代码地址
https://gitee.com/xinshuwei/ra6m4-environment-collector
视频演示地址
「VID_20220717_193333.mp4」https://www.aliyundrive.com/s/ieyu9fJS1nQ