ESP32 Forum

Posted: **Thu May 12, 2022 4:08 pm**

I use ESP32-Wrover-B and SHT35. I am trying to get it to display it's readings on web server. I get "Seeed_SHT35 does not name a type" error when I try to compile the code. What am I doing wrong?

Code: [Select all] [Expand/Collapse]

#include "WiFi.h"
#include "ESPAsyncWebServer.h"
#include <Arduino.h>
#include <Wire.h>
#include <Seeed_SHT35.h>
 
// Replace with your network credentials
const char* ssid = "MySSID";
const char* password = "MyPassword";
 
SHT35 sht35 = SHT35();
 
// Create AsyncWebServer object on port 80
AsyncWebServer server(80);
 
  String readSHT35Temperature(){
  
  float t = sht35.readTemperature();
 
  if (! sht35.begin(0x44))        // Set to 0x45 for alternate i2c addr
{ 
Serial.println("SHT35 test");
while (1) delay(1);
}
 
  if (isnan(t)) {    
    Serial.println("Failed to read temperature!");
    return "--";
  }
  else {
    Serial.print("");
    Serial.print("Temperature: ");
    Serial.println(t);
    return String(t);
  }
}
 
String readSHT35Humidity() {
 
  float h = sht35.readHumidity();
  if (isnan(h)) {
    Serial.println("Failed to read Humidity!");
    return "--";
  }
  else {
    Serial.print("Humidity: ");
    Serial.println(h);
    Serial.println("");
    return String(h);
  }
}
 
const char index_html[] PROGMEM = R"rawliteral(
<!DOCTYPE HTML><html>
<head>
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.7.2/css/all.css" integrity="sha384-fnmOCqbTlWIlj8LyTjo7mOUStjsKC4pOpQbqyi7RrhN7udi9RwhKkMHpvLbHG9Sr" crossorigin="anonymous">
  <style>
    html {
     font-family: Arial;
     display: inline-block;
     margin: 0px auto;
     text-align: center;
    }
    h2 { font-size: 3.0rem; }
    p { font-size: 3.0rem; }
    .units { font-size: 1.2rem; }
    .sht35-labels{
      font-size: 1.5rem;
      vertical-align:middle;
      padding-bottom: 15px;
    }
  </style>
</head>
<body>
  <h2>ESP32 SHT35 Web Server</h2>
  <p>
    <i class="fas fa-thermometer-half" style="color:#059e8a;"></i> 
    <span class="sht35-labels">Temperature</span> 
    <span id="temperature">%TEMPERATURE%</span>
    <sup class="units">&deg;C</sup>
  </p>
  <p>
    <i class="fas fa-tint" style="color:#00add6;"></i> 
    <span class="sht35-labels">Humidity</span>
    <span id="humidity">%HUMIDITY%</span>
    <sup class="units">%</sup>
  </p>
</body>
<script>
setInterval(function ( ) {
  var xhttp = new XMLHttpRequest();
  xhttp.onreadystatechange = function() {
    if (this.readyState == 4 && this.status == 200) {
      document.getElementById("temperature").innerHTML = this.responseText;
    }
  };
  xhttp.open("GET", "/temperature", true);
  xhttp.send();
}, 10000 ) ;
 
setInterval(function ( ) {
  var xhttp = new XMLHttpRequest();
  xhttp.onreadystatechange = function() {
    if (this.readyState == 4 && this.status == 200) {
      document.getElementById("humidity").innerHTML = this.responseText;
    }
  };
  xhttp.open("GET", "/humidity", true);
  xhttp.send();
}, 10000 ) ;
</script>
</html>)rawliteral";
 
// Replaces placeholder with sht35 values
String processor(const String& var){
  //Serial.println(var);
  if(var == "TEMPERATURE"){
    return readSHT35Temperature();
  }
  else if(var == "HUMIDITY"){
    return readSHT35Humidity();
  }
  return String();
}
 
void setup(){
  // Serial port for debugging purposes
  Serial.begin(115200);
  
  // Connect to Wi-Fi
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.println("Connecting to WiFi..");
  }
 
  // Print ESP32 Local IP Address
  Serial.println(WiFi.localIP());
 
  // Route for root / web page
  server.on("/", HTTP_GET, [](AsyncWebServerRequest *request){
    request->send_P(200, "text/html", index_html, processor);
  });
  server.on("/temperature", HTTP_GET, [](AsyncWebServerRequest *request){
    request->send_P(200, "text/plain", readSHT35Temperature().c_str());
  });
  server.on("/humidity", HTTP_GET, [](AsyncWebServerRequest *request){
    request->send_P(200, "text/plain", readSHT35Humidity().c_str());
  });
 
  // Start server
  server.begin();
}
 
void loop(){
  
}

ESP32 Forum

Unable to get SHT35 working with web server.

Unable to get SHT35 working with web server.