Send TXT File to a webpage from an SD CARD through ESP8266

Hi everyone,

I am currently building a module that is able to send data to a webpage. I am using an MKR ZERO Arduino. Basically, I am able so far to send a simple HTML GET request which is treated by a php file. Then, it sends everything to a mySQL data base. The GET request is sent from the Arduino to the webpage. Then, the php file does the rest of the job. First, this is what my arduino code looks like :

void sendSQL(){
  Serial1.println("AT+CIPSTART=1,\"TCP\",\"" + server + "\",80");
  if( Serial1.find("OK")){
    Serial.println("TCP connection ready");

    String postRequest = "GET " + uri + "?location=" + "\'" + location + "\'" +
      "&sun_influence=" + "\'" + sunInfluence + "\'" + "&module_name=" + "\'" + moduleName + "\'" + " 
      HTTP/1.1\r\nHost: " + server + "\r\n\r\n";
    Serial1.println("AT+CIPSEND=1," + String(postRequest.length()));  
    Serial.println("AT+CIPSEND=1," + String(postRequest.length()));  
      if(Serial1.find(">")) { 
        if(Serial1.find("SEND OK")){ 
          Serial.println("Packet sent");
          Serial.println("Packet cannot be sent");
      Serial.println("Nothing received");
    Serial.println("TCP connection failed");   

The php file looks like this :


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

// Create connection
$conn = new mysqli($servername, $username,$password, $dbname);

// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);

$val1 = $_GET['location'];
$val2 = $_GET['sun_influence'];
$val3 = $_GET['module_name'];

$sql = "INSERT INTO room(location,sun_influence,module_name) VALUES ($val1,$val2,$val3);";

if ($conn->query($sql) === TRUE) {
    echo "Room parameters Saved Successfully!";
} else {
    echo "Error:" . $sql . "
" . $conn->error;



All of that part works pretty well! Unfortunately, I won't be able to use this solution in my case. Indeed, that would mean sending data at each end of a test (approximately 1 minute), which is a waste of energy. And in my situation, my module is supplied by a 3.3V battery. My idea is to gather a maximum of data in the SD card of my MKR ZERO, and to send everything at once every 30 minutes, for example. Then, I would waste less energy.

The thing is I'm not that good in HTTP/Php treatment, that's why I'm asking for some help. My idea is to create a text file in my SD CARD (I already know how to do that), and to send it after 30 minutes to the webpage. Is it possible to do that through a HTML request? Then, how am I suppose to treat the data in the php file? The php should be able to send each test to the data base line per line. Maybe my solution is not smart, so I'm open about hearing any kind of suggestion!

Thank you very much!


    String postRequest = "GET "

I suppose that you'd store a POST request in a variable called getRequest...

You COULD make a POST request, where the body of the request is all the data in the file in the SD card.

The actual POST request looks a lot like a GET request, except that the data goes at the end of the headers, after a blank line.

Of course, your PHP script will need to change, to deal with the bucket of data, instead of nicely formatted variables.

GET and POST requests are NOT sent to web pages. A web page is something that a browser displays, containing the reply from the script on the server.

Why do you think that sending the results of, say, thirty tests at once will be better than making 30 requests with data from one test?