ESP8266上获取BME280的数据

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Tuesday, 02 February 2021

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ESP8266和BME280搭建气象站

使用ESP8266和BME280搭建气象站，在此项目中，您将创建一个网页，以图形方式显示传感器读数，构建一个ESP32或ESP8266客户端，该客户端向PHP脚本发出请求以在MySQL数据库中发布传感器读数

配件清单：

ESP8266

BME280

面包板

杜邦线

0.96的LED屏幕

开发环境：

Arduino IDE 1.8.9

PHP的运行环境：PHP+mysql+apache

PHP 7.1.31

Apache 2.4.41

Mysql 5.7.27

配件介绍：

ESP8266：NodeMCU,是一个开源的物联网平台。它使用Lua脚本语言编程。该平台基于eLua 开源项目,底层使用ESP8266 sdk 0.9.5版本。该平台使用了很多开源项目, 例如 lua-cjson, spiffs. NodeMCU包含了可以运行在 esp8266 Wi-Fi SoC芯片之上的固件,以及基于ESP-12模组的硬件。

BME280：该传感器是一款集成温度、湿度、气压，三位一体的环境传感器。具有高精度，多功能，小尺寸等特点。DFRobot Gravity I2C BME280环境传感器采用Gravity-I2C接口设计，同时预留预留SPI接口，可以方便快捷的搭建产品原型，应用于环境监测，楼层高度检测，物联网控制等各种应用场景。

硬件连线图：

源代码：

下载库文件：

l在Arduino IDE中安装ESP8266开发板 https://randomnerdtutorials.com/how-to-install-esp8266-board-arduino-ide/

l在Arduino IDE中安装BME280库和Adafruit_Sensor库：https://randomnerdtutorials.com/esp8266-bme280-arduino-ide/

代码逻辑

发送传感器数值到服务器

http.begin(serverName);

// Specify content-type header
http.addHeader("Content-Type", "application/x-www-form-urlencoded");

// Prepare your HTTP POST request data
String httpRequestData = "api_key=" + apiKeyValue + "&value1=" 
                       + String(bme.readTemperature()) 
                       + "&value2=" + String(bme.readHumidity()) 
                       + "&value3=" + String(bme.readPressure()/100.0F) + "";

int httpResponseCode = http.POST(httpRequestData);

完整代码：

Sql文件

CREATE TABLE Sensor (
    id INT(6) UNSIGNED AUTO_INCREMENT PRIMARY KEY,
    value1 VARCHAR(10),
    value2 VARCHAR(10),
    value3 VARCHAR(10),
    reading_time TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
)

php文件 用来向数据库保存数据

<?php
$servername = "localhost";
$dbname = "REPLACE_WITH_YOUR_DATABASE_NAME";
$username = "REPLACE_WITH_YOUR_USERNAME";
$password = "REPLACE_WITH_YOUR_PASSWORD";
$api_key_value = "tPmAT5Ab3j7F9";
$api_key = $value1 = $value2 = $value3 = "";
if ($_SERVER["REQUEST_METHOD"] == "POST") {
    $api_key = test_input($_POST["api_key"]);
    if($api_key == $api_key_value) {
        $value1 = test_input($_POST["value1"]);
        $value2 = test_input($_POST["value2"]);
        $value3 = test_input($_POST["value3"]);
        $conn = new mysqli($servername, $username, $password, $dbname);
        if ($conn->connect_error) {
            die("Connection failed: " . $conn->connect_error);
        } 
        $sql = "INSERT INTO Sensor (value1, value2, value3)
        VALUES ('" . $value1 . "', '" . $value2 . "', '" . $value3 . "')";
        if ($conn->query($sql) === TRUE) {
            echo "New record created successfully";
        } 
        else {
            echo "Error: " . $sql . "<br>" . $conn->error;
        }
        $conn->close();
    }
    else {
        echo "Wrong API Key provided.";
    }
}
else {
    echo "No data posted with HTTP POST.";
}
function test_input($data) {
    $data = trim($data);
    $data = stripslashes($data);
    $data = htmlspecialchars($data);
    return $data;
}

php文件 将数据花为折线图

<?php
$servername = "localhost";
$dbname = "REPLACE_WITH_YOUR_DATABASE_NAME";
$username = "REPLACE_WITH_YOUR_USERNAME";
$password = "REPLACE_WITH_YOUR_PASSWORD";
$conn = new mysqli($servername, $username, $password, $dbname);
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
} 
$sql = "SELECT id, value1, value2, value3, reading_time FROM Sensor order by reading_time desc limit 40";
$result = $conn->query($sql);
while ($data = $result->fetch_assoc()){
    $sensor_data[] = $data;
}
$readings_time = array_column($sensor_data, 'reading_time');
$value1 = json_encode(array_reverse(array_column($sensor_data, 'value1')), JSON_NUMERIC_CHECK);
$value2 = json_encode(array_reverse(array_column($sensor_data, 'value2')), JSON_NUMERIC_CHECK);
$value3 = json_encode(array_reverse(array_column($sensor_data, 'value3')), JSON_NUMERIC_CHECK);
$reading_time = json_encode(array_reverse($readings_time), JSON_NUMERIC_CHECK);
$result->free();
$conn->close();
?>
<!DOCTYPE html>
<html>
<meta name="viewport" content="width=device-width, initial-scale=1">
  <script src="https://code.highcharts.com/highcharts.js"></script>
  <style>
    body {
      min-width: 310px;
    	max-width: 1280px;
    	height: 500px;
      margin: 0 auto;
    }
    h2 {
      font-family: Arial;
      font-size: 2.5rem;
      text-align: center;
    }
  </style>
  <body>
    <h2>ESP Weather Station</h2>
    <div id="chart-temperature" class="container"></div>
    <div id="chart-humidity" class="container"></div>
    <div id="chart-pressure" class="container"></div>
<script>
var value1 = <?php echo $value1; ?>;
var value2 = <?php echo $value2; ?>;
var value3 = <?php echo $value3; ?>;
var reading_time = <?php echo $reading_time; ?>;
var chartT = new Highcharts.Chart({
  chart:{ renderTo : 'chart-temperature' },
  title: { text: 'BME280 Temperature' },
  series: [{
    showInLegend: false,
    data: value1
  }],
  plotOptions: {
    line: { animation: false,
      dataLabels: { enabled: true }
    },
    series: { color: '#059e8a' }
  },
  xAxis: { 
    type: 'datetime',
    categories: reading_time
  },
  yAxis: {
    title: { text: 'Temperature (Celsius)' }
  },
  credits: { enabled: false }
});
var chartH = new Highcharts.Chart({
  chart:{ renderTo:'chart-humidity' },
  title: { text: 'BME280 Humidity' },
  series: [{
    showInLegend: false,
    data: value2
  }],
  plotOptions: {
    line: { animation: false,
      dataLabels: { enabled: true }
    }
  },
  xAxis: {
    type: 'datetime',
    categories: reading_time
  },
  yAxis: {
    title: { text: 'Humidity (%)' }
  },
  credits: { enabled: false }
});
var chartP = new Highcharts.Chart({
  chart:{ renderTo:'chart-pressure' },
  title: { text: 'BME280 Pressure' },
  series: [{
    showInLegend: false,
    data: value3
  }],
  plotOptions: {
    line: { animation: false,
      dataLabels: { enabled: true }
    },
    series: { color: '#18009c' }
  },
  xAxis: {
    type: 'datetime',
    categories: reading_time
  },
  yAxis: {
    title: { text: 'Pressure (hPa)' }
  },
  credits: { enabled: false }
});
</script>
</body>
</html>

Arduino文件 用来向数据库保存数据

#ifdef ESP32
  #include <WiFi.h>
  #include <HTTPClient.h>
#else
  #include <ESP8266WiFi.h>
  #include <ESP8266HTTPClient.h>
  #include <WiFiClient.h>
#endif
#include <Wire.h>
#include <Adafruit_Sensor.h>
#include <Adafruit_BME280.h>
const char* ssid     = "REPLACE_WITH_YOUR_SSID";
const char* password = "REPLACE_WITH_YOUR_PASSWORD";
const char* serverName = "http://example.com/post-data.php";
String apiKeyValue = "tPmAT5Ab3j7F9";
Adafruit_BME280 bme; 
void setup() {
  Serial.begin(115200);
  WiFi.begin(ssid, password);
  Serial.println("Connecting");
  while(WiFi.status() != WL_CONNECTED) { 
    delay(500);
    Serial.print(".");
  }
  Serial.println("");
  Serial.print("Connected to WiFi network with IP Address: ");
  Serial.println(WiFi.localIP());
  bool status = bme.begin(0x76);
  if (!status) {
    Serial.println("Could not find a valid BME280 sensor, check wiring or change I2C address!");
    while (1);
  }
}
void loop() {
  if(WiFi.status()== WL_CONNECTED){
    HTTPClient http;
    http.begin(serverName);
    http.addHeader("Content-Type", "application/x-www-form-urlencoded");
    String httpRequestData = "api_key=" + apiKeyValue + "&value1=" + String(bme.readTemperature())+ "&value2=" + String(bme.readHumidity()) + "&value3=" + String(bme.readPressure()/100.0F) + "";
    Serial.print("httpRequestData: ");
    Serial.println(httpRequestData);
    int httpResponseCode = http.POST(httpRequestData);
    if (httpResponseCode>0) {
      Serial.print("HTTP Response code: ");
      Serial.println(httpResponseCode);
    }
    else {
      Serial.print("Error code: ");
      Serial.println(httpResponseCode);
    }
    http.end();
  }
  else {
    Serial.println("WiFi Disconnected");
  }
  delay(30000);  
}

实验结果：

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