small fix ESP8266 Arduino DHT22 example

small fix ESP8266 Arduino DHT22 example

Author: iot-playground

Esp8266EasyIoT/examples/esp8266easyiot_temperature_humidity/esp8266easyiot_temperature_humidity.ino

@@ -1,7 +1,7 @@
  /*
- V1.0 - first version
+ V2.0 - small fix
  
- Created by Igor Jarc <igor.jarc1@gmail.com>
+ Created by Igor Jarc <admin@iot-playground.com>
  See http://iot-playground.com for details
  
  This program is free software; you can redistribute it and/or
@@ -17,6 +17,9 @@
 #define HUMIDITY_SENSOR_DIGITAL_PIN 2
 
 
+#define SEND_INTERVAL  1000 * 30 // 30S  
+
+
 Esp8266EasyIoT esp; 
 
 SoftwareSerial serialEsp(10, 11);
@@ -29,6 +32,7 @@ float lastHum;
 Esp8266EasyIoTMsg msgHum(CHILD_ID_HUM, V_HUM);
 Esp8266EasyIoTMsg msgTemp(CHILD_ID_TEMP, V_TEMP);
 
+unsigned long startTime;
 
 void setup()
 {
@@ -37,7 +41,6 @@ void setup()
 
   Serial.println("EasyIoTEsp init");
 
-
   esp.begin(NULL, 3, &serialEsp, &Serial);
   //esp.begin(NULL, &serialEsp);
   dht.setup(HUMIDITY_SENSOR_DIGITAL_PIN); 
@@ -49,40 +52,63 @@ void setup()
 
 //  Serial.println("present S_TEMP");
   esp.present(CHILD_ID_TEMP, S_TEMP);
+  
+  
+  startTime = millis()+SEND_INTERVAL;
 
 }
 
 void loop()
 {  
   while(!esp.process());
 
-  delay(dht.getMinimumSamplingPeriod());
-
-  while(!esp.process());
-
-  float temperature = dht.getTemperature();
-  if (isnan(temperature)) {
-    Serial.println("Failed reading temperature from DHT");
-  } 
-  else if (temperature != lastTemp) 
+  if (IsTimeout())
   {
-    lastTemp = temperature;
-    esp.send(msgTemp.set(temperature, 1));
-    Serial.print("T: ");
-    Serial.println(temperature);
+    startTime = millis();
+
+    float temperature = dht.getTemperature();
+    if (isnan(temperature)) {
+      Serial.println("Failed reading temperature from DHT");
+    } 
+    else if (temperature != lastTemp) 
+    {
+      lastTemp = temperature;
+      esp.send(msgTemp.set(temperature, 1));
+      Serial.print("T: ");
+      Serial.println(temperature);
+    }
+  
+    while(!esp.process());
+  
+    float humidity = dht.getHumidity();
+    if (isnan(humidity)) {
+      Serial.println("Failed reading humidity from DHT");
+    } 
+    else if (humidity != lastHum) 
+    {
+      lastHum = humidity;
+      esp.send(msgHum.set(humidity, 1));
+      Serial.print("H: ");
+      Serial.println(humidity);
+    }
   }
+}
 
-  float humidity = dht.getHumidity();
-  if (isnan(humidity)) {
-    Serial.println("Failed reading humidity from DHT");
-  } 
-  else if (humidity != lastHum) 
+boolean IsTimeout()
+{
+  unsigned long now = millis();
+  if (startTime <= now)
   {
-    lastHum = humidity;
-    esp.send(msgHum.set(humidity, 1));
-    Serial.print("H: ");
-    Serial.println(humidity);
+    if ( (unsigned long)(now - startTime )  < SEND_INTERVAL ) 
+      return false;
   }
+  else
+  {
+    if ( (unsigned long)(startTime - now) < SEND_INTERVAL ) 
+      return false;
+  }
+
+  return true;
 }