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--- en:iot:examples:dht [2021/03/05 00:16] – heiko.pikner
+++ 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 13: / Line 13: @@
 <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.
+<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 Temperature & humidity shield uses
+// Includes global variables and librarys that the DHT uses
 #include <Arduino.h>
 #include <ittiot.h>
+#include <Ticker.h>
 #include <DHT.h>
@@ Line 23: / Line 26: @@
 #define WIFI_PASSWORD "password"
-#define DHTPIN D4     // what pin we're connected to. Change this to D3 if your shield has one leg removed.
+#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 38: / Line 56: @@
 void setup()
 {
+  // Initialize serial port and send message
   Serial.begin(115200); // setting up serial connection parameter
   Serial.println("Booting");
@@ Line 43: / Line 62: @@
   //iot.setConfig("wname", WIFI_NAME);
   //iot.setConfig("wpass", WIFI_PASSWORD);
-  iot.printConfig(); // print json config to serial
+  iot.printConfig(); // print IoT json config to serial
   iot.setup(); // Initialize IoT library
-  pinMode(16, OUTPUT);
+  // Initialize DHT library
-  dht.begin(); // activating temperature and humidity functions
+  dht.begin();
+  // Initialize Ticker interval and callback
+  timeTicker.attach(1, sendData);
 }
@@ Line 54: / Line 76: @@
   iot.handle(); // IoT behind the plan work, it should be periodically called
-  float h = dht.readHumidity(); // reading humidity values
+  if(sendDataFlag)
-  float t = dht.readTemperature(); // reading temperature values
+  {
+    sendDataFlag = false;
+    // Read humidity and temperature
+    float h = dht.readHumidity();
+    float t = dht.readTemperature();
+    // Create a buffer to store strings to being sent later
+    char buf[10];
-  char buf[10]; // Put whatever length you need here, defining char variable
+    // Convert temperature value messages to strings and send to the MQTT server
-  String(t).toCharArray(buf,10); // converting temperature value into string
+    String(t).toCharArray(buf,10);
-  digitalWrite(16,HIGH);
+    iot.publishMsg("temp",buf);
-  iot.publishMsg("temp",buf); // publishing temperature value to MQTT broker
-  delay(2000); // wait 2 seconds
-  digitalWrite(16,LOW);
+    // Convert humidity value messages to strings and send to the MQTT server
-  String(h).toCharArray(buf,10); // converting humidity value into string
+    String(h).toCharArray(buf,10);
-  iot.publishMsg("hum",buf); // publishing humidity value to MQTT broker
+    iot.publishMsg("hum",buf);
-  delay(2000); // wait 2 seconds
+  }
 }
 </code>

en/iot/examples/dht.1614903362.txt.gz · Last modified: 2021/03/05 10:00 (external edit)