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--- en:iot:examples:dht [2018/02/27 14:18] – Somepub
+++ en:iot:examples:dht [Unknown date] (current) – external edit (Unknown date) 127.0.0.1
@@ Line 1: / Line 1: @@
-====== DHT  example======
+====== Temp/Hum example======
 DHT module must be connected to controller module or with sensor module.
@@ Line 5: / Line 5: @@
 {{:en:iot:examples:dhtpicture1.jpg?200|}}
 {{:en:iot:examples:dhtpicture2.jpg?200|}}
+NB! If your DHT shield has one leg removed as in the picture below, please change the #define DHTPIN D4 to D3 in the program code.
+{{:en:iot:examples:dht_hack.jpg?200|}}
 Needed libraries:
-<code>ITTIoT, Adafruit DHT Unified</code>
+<code>lib_deps = ITTIoT, DHT sensor library, Adafruit Unified Sensor</code>
-The example code above will print out current Tempeture and Humidity in the room
+The example code above will print out current Tempeture and Humidity in the room.
-<code c>
+<fc #ff0000>After programming, if NAN appears instead of readings, the USB cable should be disconnected and reconnected!</fc>
+<code c>
+// Includes global variables and librarys that the DHT uses
 #include <Arduino.h>
 #include <ittiot.h>
+#include <Ticker.h>
 #include <DHT.h>
-#define DHTPIN D4     // what pin we're connected to
+#define WIFI_NAME "name"
+#define WIFI_PASSWORD "password"
+#define DHTPIN D3     // Pin where DHT shield is connected. Change this to D4 if the shield has no legs removed.
 #define DHTTYPE DHT22   // DHT 22  (AM2302)
+// Create an object for DHT sensor
 DHT dht(DHTPIN, DHTTYPE);
+// Create an object for Ticker library
+Ticker timeTicker;
+bool sendDataFlag;
+// Ticker library callback, which will occur 0.5 second interval.
+void sendData()
+{
+  sendDataFlag=true;
+}
+void iot_received(String topic, String msg) {}
+// Function started after the connection to the server is established.
 void iot_connected()
 {
+  // Send message to serial port to show that connection is established
   Serial.println("MQTT connected callback");
+  // Send message to MQTT server to show that connection is established
   iot.log("IoT DHT example!");
 }
@@ Line 29: / Line 56: @@
 void setup()
 {
-  Serial.begin(115200);
+  // Initialize serial port and send message
+  Serial.begin(115200); // setting up serial connection parameter
   Serial.println("Booting");
-  iot.printConfig(); // print json config to serial //Peale Serial.begin ja enne iot.setup
-  iot.setup();
+  //iot.setConfig("wname", WIFI_NAME);
-  pinMode(16, OUTPUT);
+  //iot.setConfig("wpass", WIFI_PASSWORD);
+  iot.printConfig(); // print IoT json config to serial
+  iot.setup(); // Initialize IoT library
+  // Initialize DHT library
   dht.begin();
+  // Initialize Ticker interval and callback
+  timeTicker.attach(1, sendData);
 }
 void loop()
 {
-  iot.handle();
+  iot.handle(); // IoT behind the plan work, it should be periodically called
-  float h = dht.readHumidity();
+  if(sendDataFlag)
-	float t = dht.readTemperature();
+  {
+    sendDataFlag = false;
+    // Read humidity and temperature
+    float h = dht.readHumidity();
+    float t = dht.readTemperature();
-  char buf[10]; // Put whatever length you need here
+    // Create a buffer to store strings to being sent later
-	String(t).toCharArray(buf,10);
+    char buf[10];
-  digitalWrite(16,HIGH);
+    // Convert temperature value messages to strings and send to the MQTT server
-  iot.publishMsg("temp",buf);
+    String(t).toCharArray(buf,10);
-	delay(2000);
+    iot.publishMsg("temp",buf);
-  digitalWrite(16,LOW);
-	String(h).toCharArray(buf,10);
+    // Convert humidity value messages to strings and send to the MQTT server
-  iot.publishMsg("hum",buf);
+    String(h).toCharArray(buf,10);
-	delay(2000);
+    iot.publishMsg("hum",buf);
+  }
 }
 </code>

en/iot/examples/dht.1519741107.txt.gz · Last modified: 2020/07/20 09:00 (external edit)