ESP MQTT Scale with OTA Update Code

mqttscaleOTA.ino

#include <WiFi.h>
#include <WiFiClient.h>
#include <WebServer.h>
#include <ESPmDNS.h>
#include <Update.h>
#include <HX711_ADC.h>
#include <PubSubClient.h>
char msg_buff[50];

const char* host = "esp32";
const char* ssid = "yourssid";
const char* password = "yourpassword";
const char* mqtt_server = "192.168.1.117";
float calibration_factor = 115.50; //115.50 worked for my scale ;
int switchValue;

//MQTT Setup
WiFiClient esp32Client;
PubSubClient client(esp32Client);

//HX711 Constructor (dout, sck):
HX711_ADC LoadCell(19, 18);

const int eepromAdress = 0;

long t;

WebServer server(80);

/*
   Login page
*/

const char* loginIndex =
  "<form name='loginForm'>"
  "<table width='20%' bgcolor='A09F9F' align='center'>"
  "<tr>"
  "<td colspan=2>"
  "<center><font size=4><b>ESP32 Login Page</b></font></center>"
  "<br>"
  "</td>"
  "<br>"
  "<br>"
  "</tr>"
  "<td>Username:</td>"
  "<td><input type='text' size=25 name='userid'><br></td>"
  "</tr>"
  "<br>"
  "<br>"
  "<tr>"
  "<td>Password:</td>"
  "<td><input type='Password' size=25 name='pwd'><br></td>"
  "<br>"
  "<br>"
  "</tr>"
  "<tr>"
  "<td><input type='submit' onclick='check(this.form)' value='Login'></td>"
  "</tr>"
  "</table>"
  "</form>"
  "<script>"
  "function check(form)"
  "{"
  "if(form.userid.value=='admin' && form.pwd.value=='admin')"
  "{"
  "window.open('/serverIndex')"
  "}"
  "else"
  "{"
  " alert('Error Password or Username')/*displays error message*/"
  "}"
  "}"
  "</script>";

/*
   Server Index Page
*/

const char* serverIndex =
  "<script src='https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js'></script>"
  "<form method='POST' action='#' enctype='multipart/form-data' id='upload_form'>"
  "<input type='file' name='update'>"
  "<input type='submit' value='Update'>"
  "</form>"
  "<div id='prg'>progress: 0%</div>"
  "<script>"
  "$('form').submit(function(e){"
  "e.preventDefault();"
  "var form = $('#upload_form')[0];"
  "var data = new FormData(form);"
  " $.ajax({"
  "url: '/update',"
  "type: 'POST',"
  "data: data,"
  "contentType: false,"
  "processData:false,"
  "xhr: function() {"
  "var xhr = new window.XMLHttpRequest();"
  "xhr.upload.addEventListener('progress', function(evt) {"
  "if (evt.lengthComputable) {"
  "var per = evt.loaded / evt.total;"
  "$('#prg').html('progress: ' + Math.round(per*100) + '%');"
  "}"
  "}, false);"
  "return xhr;"
  "},"
  "success:function(d, s) {"
  "console.log('success!')"
  "},"
  "error: function (a, b, c) {"
  "}"
  "});"
  "});"
  "</script>";

/*
   setup function
*/

void setup() {
  delay(100);
  pinMode(BUILTIN_LED, OUTPUT);
  pinMode(23, INPUT_PULLUP);
  Serial.begin(115200);
  Serial.println("HX711 Calibration");
  setup_wifi();
  client.setServer(mqtt_server, 1883);
  client.setCallback(callback);
  scale_setup();
}
void setup_wifi() {


  // Connect to WiFi network
  WiFi.begin(ssid, password);
  Serial.println("");

  // Wait for connection
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("");
  Serial.print("Connected to ");
  Serial.println(ssid);
  Serial.print("IP address: ");
  Serial.println(WiFi.localIP());
  
  /*use mdns for host name resolution*/
  if (!MDNS.begin(host)) { //http://esp32.local
    Serial.println("Error setting up MDNS responder!");
    while (1) {
      delay(1000);
    }
  }
  Serial.println("mDNS responder started");
  /*return index page which is stored in serverIndex */
  server.on("/", HTTP_GET, []() {
    server.sendHeader("Connection", "close");
    server.send(200, "text/html", loginIndex);
  });
  server.on("/serverIndex", HTTP_GET, []() {
    server.sendHeader("Connection", "close");
    server.send(200, "text/html", serverIndex);
  });
  /*handling uploading firmware file */
  server.on("/update", HTTP_POST, []() {
    server.sendHeader("Connection", "close");
    server.send(200, "text/plain", (Update.hasError()) ? "FAIL" : "OK");
    ESP.restart();
  }, []() {
    HTTPUpload& upload = server.upload();
    if (upload.status == UPLOAD_FILE_START) {
      Serial.printf("Update: %s\n", upload.filename.c_str());
      if (!Update.begin(UPDATE_SIZE_UNKNOWN)) { //start with max available size
        Update.printError(Serial);
      }
    } else if (upload.status == UPLOAD_FILE_WRITE) {
      /* flashing firmware to ESP*/
      if (Update.write(upload.buf, upload.currentSize) != upload.currentSize) {
        Update.printError(Serial);
      }
    } else if (upload.status == UPLOAD_FILE_END) {
      if (Update.end(true)) { //true to set the size to the current progress
        Serial.printf("Update Success: %u\nRebooting...\n", upload.totalSize);
      } else {
        Update.printError(Serial);
      }
    }
  });
  server.begin();
}

void scale_setup() {
  client.subscribe("HX711cal1");
  Serial.println("HX711 Calibration");
  Serial.println("Remove all weight from scale");
  Serial.println("After readings begin, place known weight on scale");
  Serial.println("Press a,s,d,f to increase calibration factor by 10,100,1000,10000 respectively");
  Serial.println("Press z,x,c,v to decrease calibration factor by 10,100,1000,10000 respectively");
  Serial.println("Press t for tare");
  LoadCell.begin();
  long stabilisingtime = 2000; // tare preciscion can be improved by adding a few seconds of stabilising time
  LoadCell.start(stabilisingtime);
  if (LoadCell.getTareTimeoutFlag()) {
    Serial.println("Tare timeout, check MCU>HX711 wiring and pin designations");
  }
  else {
    LoadCell.setCalFactor(calibration_factor); // set calibration value (float)
    Serial.println("Startup + tare is complete");
  };
}

void callback(char* topic, byte* payload, unsigned int length) {
  int i = 0;
  Serial.println("Message arrived:  topic: " + String(topic));
  Serial.println("Length: " + String(length, DEC));
  for (i = 0; i < length; i++) {
    msg_buff[i] = payload[i];
  }
  msg_buff[i] = '\0';

  String msgString = String(msg_buff);

  Serial.println("Payload: " + msgString);
  if (msgString == "tare") {   // if there is a "1" published to any topic (#) on the broker then:
    digitalWrite(BUILTIN_LED, LOW);     // set pin to the opposite state
    Serial.println("Switching LED");
    LoadCell.tareNoDelay();
    digitalWrite(BUILTIN_LED, HIGH);
  }
  else if (msgString == "+0.1")
    calibration_factor += 0.1;
  else if (msgString == "-0.1")
    calibration_factor -= 0.1;
  else if (msgString == "+1")
    calibration_factor += 1;
  else if (msgString == "-1")
    calibration_factor -= 1;
  else if (msgString == "+10")
    calibration_factor += 10;
  else if (msgString == "-10")
    calibration_factor -= 10;
  else if (msgString == "+100")
    calibration_factor += 100;
  else if (msgString == "-100")
    calibration_factor -= 100;
}

void reconnect() {
  while (!client.connected()) {
    Serial.print("AtinByteting MQTT connection...");
    if (client.connect("ESP8266Client")) {
      Serial.println("connected");
      client.subscribe("HX711cal1");
      client.publish("IP", WiFi.localIP().toString().c_str(), true);
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      delay(5000);

    }
  }
}


void loop(void) {

  if (!client.connected()) {
    reconnect();
  }

  server.handleClient();
  delay(1);
  
  client.loop();
  LoadCell.update();
  //get smoothed value from data set
  if (millis() > t + 250) {
    float i = LoadCell.getData();
    Serial.print("Load_cell output val: ");
    Serial.println(i);
    t = millis();
    LoadCell.setCalFactor(calibration_factor);
    client.publish("HX711calfactor1", String(calibration_factor).c_str(), true);
    client.publish("Scale2",String(i).c_str(),true);
    Serial.print(" calibration_factor: ");
    Serial.print(calibration_factor);
    Serial.println();
  }
  

  //receive from serial terminal
  if (Serial.available() > 0) {
    float i;
    char inByte = Serial.read();
    if (inByte == 't') LoadCell.tareNoDelay();
    else if (inByte == '+' || inByte == 'a')
      calibration_factor += 0.1;
    else if (inByte == '-' || inByte == 'z')
      calibration_factor -= 0.1;
    else if (inByte == 's')
      calibration_factor += 1;
    else if (inByte == 'x')
      calibration_factor -= 1;
    else if (inByte == 'd')
      calibration_factor += 10;
    else if (inByte == 'c')
      calibration_factor -= 10;
    else if (inByte == 'f')
      calibration_factor += 100;
    else if (inByte == 'v')
      calibration_factor -= 100;
  }

  //check if last tare operation is complete
  if (LoadCell.getTareStatus() == true) {
    Serial.println("Tare complete");

  }

}