Funpack第八期 Arduino nano 33 ble sense简易环境监测站

任务二：环境监测站

利用NANO-33 BLE的传感器, 搭建一个小型环境监测站用于监测户外环境。待监测的参数包括:

• 周边环境温度（精度：±0.1°C, ±0.1°F）

• 周边环境湿度（精度：±1%）

• 大气压强（精度：±0.1kPa, ±0.1psi）

• 日照强度（用于判断白天/夜晚）

• 周边平均噪声（精度：±1dB）

具体实现

需要器件：

• Arduino Nano 33 BLE sense 开发板一块
• OLED显示屏一块(SPI协议)

接线示意图

接线关系表

源码实现 读取温度和湿度

#include <Arduino_HTS221.h>
//读取温度湿度传感器所需要的库
void setup() {

  //init HTS to get Temperature and humidity
  if (!HTS.begin()) {
    Serial.println("Failed to initialize humidity temperature sensor!");
    while (1);
  }
}
void loop() {

  // read all the HTS sensor values
  float temperature = HTS.readTemperature();
  float humidity    = HTS.readHumidity();

}

读取大气压强

#include <Arduino_LPS22HB.h>
//读取大气压强传感器数据所需要的库
void setup() {

  //init LPS22HB to get air pressure
   if (!BARO.begin()) {
    Serial.println("Failed to initialize pressure sensor!");
    while (1);
  }
}
void loop() {

  //read the pressure of air
  float pressure = BARO.readPressure();

}

读取光照强度传感器

光照传感器首先读取的是周围环境的RGB值，我们通过RGB转灰度也是亮度的近似公式

Gray = 0.3*R +  0.6*G + 0.1*B

//rgb color
#include <Arduino_APDS9960.h>
// 读取光照强度所需的库
void setup() {
  
   Serial.begin(9600);
  //init APDS9960 to get rgb value
  if (!APDS.begin()) {
    Serial.println("Error initializing APDS9960 sensor.");
  }
}
void loop() {

  //read APDS sensor values
  while (! APDS.colorAvailable()) {
    delay(5);
  }
  int r, g, b;
  // read the color
  APDS.readColor(r, g, b);
  float gray = 0.3*r+0.6*g+0.1*b;  //得到光照值
}

读取噪声值

//noise 
#include <PDM.h>

#include<math.h>
// default number of output channels
static const char channels = 1;

// default PCM output frequency
static const int frequency = 16000;

// Buffer to read samples into, each sample is 16-bits
short sampleBuffer[512];

// Number of audio samples read
volatile int samplesRead;
void setup() {

// Configure the data receive callback
  PDM.onReceive(onPDMdata);
  PDM.setGain(20);
  //init PDM to get data of noise
  if (!PDM.begin(channels, frequency)) {
    Serial.println("Failed to start PDM!");
    while (1);
  }
}
void loop() {

//read the noise
  double noise = get_noise();   //获取噪音值
}
void onPDMdata() {
  // Query the number of available bytes
  int bytesAvailable = PDM.available();

  // Read into the sample buffer
  PDM.read(sampleBuffer, bytesAvailable);

  // 16-bit, 2 bytes per sample
  samplesRead = bytesAvailable / 2;
}
double get_noise()
{
  double amp=0,sum=0;
  int cnt =0;
  while(cnt<200)
  {
    if (samplesRead) {
        for (int i = 0; i < samplesRead; i++) 
        {
           sum+=double(sampleBuffer[i])*sampleBuffer[i];
        }
        cnt+=samplesRead;
        samplesRead=0;
  }
  amp = 20 *log10(10*sqrt(sum/cnt));
  return amp;
}
}

最终OLED显示

#include <Arduino.h>
#include <U8g2lib.h>

#ifdef U8X8_HAVE_HW_SPI
#include <SPI.h>
#endif
#ifdef U8X8_HAVE_HW_I2C
#include <Wire.h>
#endif

U8G2_SSD1306_128X64_NONAME_F_4W_SW_SPI u8g2(U8G2_R0, /* clock=*/ 13, /* data=*/ 11, /* cs=*/ 10, /* dc=*/ 9, /* reset=*/ 8);


void setup() {
  // put your setup code here, to run once:
  u8g2.begin();
  u8g2.enableUTF8Print();
}
void loop() {
  u8g2.clearBuffer();          // clear the internal memory
  u8g2.setFont(u8g2_font_wqy12_t_gb2312a ); // choose a suitable font
  u8g2.setCursor(0,10);
  u8g2.print("环境湿度:");
  u8g2.print(humidity);
  u8g2.print(" %");
  
  u8g2.setCursor(0,23);
  u8g2.print("环境温度:");
  u8g2.print(temperature);
  u8g2.print(" °C");
  
  u8g2.setCursor(0,36);
  u8g2.print("大气压强:");
  u8g2.print(pressure);
  u8g2.print(" kPa");
    
  u8g2.setCursor(0,49);
  u8g2.print("光照强度:");
  if(int(gray)>=20)
    u8g2.print("白天");
  else
    u8g2.print("夜晚");
  
  u8g2.setCursor(0,62);
  u8g2.print("平均噪声:");
  u8g2.print(noise);
  u8g2.print("dB");
  u8g2.sendBuffer();          // transfer internal memory to the display
  
  delay(1000);  


}

最终效果示意图

心得体会

Arduino 牛皮！