user85217: error:
C:\Users\mrtas\Desktop\sketch_may23a\sketch_may23a.ino: In function 'void setup()':

C:\Users\mrtas\Desktop\sketch_may23a\sketch_may23a.ino:41:24:
warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings]

   WiFi.begin(SSID, PASS);   //Begin WiFi
              ^     ^

code:
#include <DHT.h>
#include <WiFi.h>
#define DHTTYPE DHT11
#define DHTPIN 5

DHT dht(DHTPIN, DHTTYPE);

String msg = "GET /update?key=TWE505JXFTXDPNB3";
float temp;
char SSID;
char Pass;

int hum;

String tempC;

int error;
void updateTemp();
#define SSID "wifi name"

#define PASS "wifi pass"

#define IP "184.106.153.149"

void setup()
{
  dht.begin();
  Serial.begin(9600);
  delay(10);

  // Connect to WiFi network
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(SSID);
  WiFi.begin(SSID, PASS);     //Begin WiFi

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("");
  Serial.println("WiFi connected");
}

void loop() {
start:
  error = 0;

  temp = dht.readTemperature();
  hum = dht.readHumidity();

  char buffer[10];
  tempC = dtostrf(temp, 4, 1, buffer);
  updateTemp();

  if (error == 1) {
    goto start;
  }
  delay(5000);
  String cmd = "AT+CIPSTART=\"TCP\",\"";
  cmd += IP;
  cmd += "\",80";
  Serial.println(cmd);
  delay(2000);

  if (Serial.find("Error")) {
    return;
  }
  cmd = msg ;
  cmd += "&field1=";
  cmd += tempC;
  cmd += "&field2=";
  cmd += String(hum);
  cmd += "\r\n";
  Serial.print("AT+CIPSEND=");
  Serial.println(cmd.length());

  if (Serial.find(">")) {
    Serial.print(cmd);
  }
  else {
    Serial.println("AT+CIPCLOSE");
    //Resend...
    error = 1;
  }

  Serial.println("AT+CWMODE=1");
  delay(2000);
}

boolean connectWiFi()
{
  String cmd = "AT+CWJAP=\"";
  cmd += SSID;
  cmd += "\",\"";
  cmd += PASS;
  cmd += "\"";
  Serial.println(cmd);
  delay(5000);

  if (Serial.find("OK")) {
    return true;
  }
  return false;
}


user10794: It's basically a bug in the library which is expecting "char *" when you are supplying "const char *.
You could work around it by changing:
#define SSID "wifi name"
#define PASS "wifi pass"

to:
char SSID [] =  "wifi name";
char PASS [] =  "wifi pass";

That makes them non-const so the error message should go away.
Not tested. But that is the general idea.

85217: <p>error:</p>
<pre><code>C:\Users\mrtas\Desktop\sketch_may23a\sketch_may23a.ino: In function 'void setup()':

C:\Users\mrtas\Desktop\sketch_may23a\sketch_may23a.ino:41:24:
warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings]

   WiFi.begin(SSID, PASS);   //Begin WiFi
              ^     ^
</code></pre>
<p>code:</p>
<pre><code>#include &lt;DHT.h&gt;
#include &lt;WiFi.h&gt;
#define DHTTYPE DHT11
#define DHTPIN 5

DHT dht(DHTPIN, DHTTYPE);

String msg = &quot;GET /update?key=TWE505JXFTXDPNB3&quot;;
float temp;
char SSID;
char Pass;

int hum;

String tempC;

int error;
void updateTemp();
#define SSID &quot;wifi name&quot;

#define PASS &quot;wifi pass&quot;

#define IP &quot;184.106.153.149&quot;

void setup()
{
  dht.begin();
  Serial.begin(9600);
  delay(10);

  // Connect to WiFi network
  Serial.println();
  Serial.print(&quot;Connecting to &quot;);
  Serial.println(SSID);
  WiFi.begin(SSID, PASS);     //Begin WiFi

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(&quot;.&quot;);
  }
  Serial.println(&quot;&quot;);
  Serial.println(&quot;WiFi connected&quot;);
}

void loop() {
start:
  error = 0;

  temp = dht.readTemperature();
  hum = dht.readHumidity();

  char buffer[10];
  tempC = dtostrf(temp, 4, 1, buffer);
  updateTemp();

  if (error == 1) {
    goto start;
  }
  delay(5000);
  String cmd = &quot;AT+CIPSTART=\&quot;TCP\&quot;,\&quot;&quot;;
  cmd += IP;
  cmd += &quot;\&quot;,80&quot;;
  Serial.println(cmd);
  delay(2000);

  if (Serial.find(&quot;Error&quot;)) {
    return;
  }
  cmd = msg ;
  cmd += &quot;&amp;field1=&quot;;
  cmd += tempC;
  cmd += &quot;&amp;field2=&quot;;
  cmd += String(hum);
  cmd += &quot;\r\n&quot;;
  Serial.print(&quot;AT+CIPSEND=&quot;);
  Serial.println(cmd.length());

  if (Serial.find(&quot;&gt;&quot;)) {
    Serial.print(cmd);
  }
  else {
    Serial.println(&quot;AT+CIPCLOSE&quot;);
    //Resend...
    error = 1;
  }

  Serial.println(&quot;AT+CWMODE=1&quot;);
  delay(2000);
}

boolean connectWiFi()
{
  String cmd = &quot;AT+CWJAP=\&quot;&quot;;
  cmd += SSID;
  cmd += &quot;\&quot;,\&quot;&quot;;
  cmd += PASS;
  cmd += &quot;\&quot;&quot;;
  Serial.println(cmd);
  delay(5000);

  if (Serial.find(&quot;OK&quot;)) {
    return true;
  }
  return false;
}
</code></pre>
 10794: <p>It's basically a bug in the library which is expecting &quot;char *&quot; when you are supplying &quot;const char *.</p>
<p>You could work around it by changing:</p>
<pre><code>#define SSID &quot;wifi name&quot;
#define PASS &quot;wifi pass&quot;
</code></pre>
<p>to:</p>
<pre><code>char SSID [] =  &quot;wifi name&quot;;
char PASS [] =  &quot;wifi pass&quot;;
</code></pre>
<p>That makes them non-const so the error message should go away.</p>
<p>Not tested. But that is the general idea.</p>
