如何将php变量值发送到arduino变量？

Question

我的服务器上有一个PHP代码，准备将数据发送到Arduino，就在这里

$servername = "localhost";
$username = "root";
$password = "";
$dbname = "myelecdb";

// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
   die("Connection failed: " . $conn->connect_error);
}

$sql = "SELECT reading FROM elecdata";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
   // output data of each row
   while($row = $result->fetch_assoc()) {
       $backdata = $row["reading"];

   }
} else {
   echo "0 results";
}
$conn->close();

echo $backdata;
?> 

这是应该从PHP文件获取数据的Arduino代码

#include <ESP8266HTTPClient.h>
#include <ESP8266WiFi.h>
#include <WiFiClient.h>
#include <ESP8266WebServer.h>
#include <ESP8266mDNS.h>

#define PULSE_PIN D2  //gpio4
float totalreading;
char ssid[] = "MYWIFI";
char pass[] = "12345678USK";
int status = WL_IDLE_STATUS;

void setup() {
  Serial.begin(9600);

 while (status != WL_CONNECTED) {
   Serial.print("Attempting to connect to Network named: ");
   Serial.println(ssid);
   status = WiFi.begin(ssid, pass);
   delay(10000);
 }

pinMode(PULSE_PIN, INPUT);

}

void loop() {
digitalWrite(PULSE_PIN, HIGH);   
 delay(totalreading);                     
 digitalWrite(PULSE_PIN, LOW);    
 delay(totalreading);                      

}

并且当arduino开机时，我需要将$ backdata变量数据分配给arduino中的totalreading变量。 arduino上电时，该操作只能运行一次。因此，我认为此过程应在arduino代码的设置功能内完成。有帮助吗？

Answer 1

Youtube Tutorial

这正是我要正确执行的操作。我观看了本教程系列，它帮助我配置了网页和数据库。但是我在arduino方面遇到了一个错误，因此，如果您能解决它，我相信它会起作用。我得到的错误：Arduino Iot Project parseObject() failed