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--- en:iot:examples:smartventilator [2018/05/04 07:06] – created rim.puks
+++ en:iot:examples:smartventilator [Unknown date] (current) – external edit (Unknown date) 127.0.0.1
@@ Line 1: / Line 1: @@
 ====== Smart ventilator example ======
+This example shows how to make a temperature sensor controlled ventilator. You will need 2 controller modules. One
+with DHT shield attached and the other with relay shield.
+{{:en:iot:examples:20200610_212520.jpg?300|IoT controllers with DHT and relay shields}}
+Once the code has been uploaded, the DHT controller will publish the temperature and humidity values to "temp" and "hum" every 2 seconds. The relay module subscribes to topics "temp" and "conf". The relay controller will switch the relay if the temperature rises above the set limit (default:28 degrees). To change the set limit, send a new value to the "conf" topic. (For example: "25.5")
+The following is the code for the controller with relay module.
+Required libraries:
+<code>lib_deps = ITTIoT</code>
+<code c>
+// Includes global variables and librarys that the relay uses
+#include <Arduino.h>
+#include <ittiot.h>
+#define WIFI_NAME "name"
+#define WIFI_PASSWORD "password"
+// Change it according to the real name of the red IoT module where
+// temperature & humidity shield is connected
+#define DHT_TOPIC "ESP30"
+#define RELAY_PIN 5 // The relay has been connected to pin 5
+float t; //for holding the received temperature float value
+float tempLimit = 28; //the temperature limit on what the relay will switch
+// Message received
+void iot_received(String topic, String msg)
+{
+  t=msg.toFloat(); // Converts received temperature value into a real number
+  // Check if topic contains configuration data (change the temperature limit value)
+  if(topic == (DHT_TOPIC"/conf"))
+  {
+    //re-configures the temperature limit
+    tempLimit=t;
+  }
+  // Check if topic contains temperature data
+  if(topic == (DHT_TOPIC"/temp"))
+  {
+    // Relay switching according to the temperature limit value
+    if(t >= tempLimit)
+    {
+      digitalWrite(RELAY_PIN, HIGH);
+    }
+    else
+    {
+      digitalWrite(RELAY_PIN, LOW);
+    }
+  }
+}
+// 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");
+  // Subscribe to get temperature and temperature configuration messages
+  iot.subscribe(DHT_TOPIC"/temp");
+  iot.subscribe(DHT_TOPIC"/conf");
+  // Send message to MQTT server to show that connection is established
+  iot.log("Ventilator example!");
+}
+void setup()
+{
+  // Initialize serial port and send message
+  Serial.begin(115200); // setting up serial connection parameter
+  Serial.println("Booting");
+  //iot.setConfig("wname", WIFI_NAME);
+  //iot.setConfig("wpass", WIFI_PASSWORD);
+  iot.printConfig(); // print IoT json config to serial
+  iot.setup(); // Initialize IoT library
+  pinMode(RELAY_PIN, OUTPUT); // The relay pin is defined as output type
+}
+void loop()
+{
+  iot.handle(); // IoT behind the plan work, it should be periodically called
+  delay(20); // Wait 0.2 second
+}
+</code>
+The following is the program code for the controller with DHT module.
+Required libraries:
+<code>lib_deps = ITTIoT, DHT sensor library, Adafruit Unified Sensor</code>
+<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 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;
+}
+// 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!");
+}
+void setup()
+{
+  // Initialize serial port and send message
+  Serial.begin(115200); // setting up serial connection parameter
+  Serial.println("Booting");
+  //iot.setConfig("wname", WIFI_NAME);
+  //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 behind the plan work, it should be periodically called
+  if(sendDataFlag)
+  {
+    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];
+    // Convert temperature value messages to strings and send to the MQTT server
+    String(t).toCharArray(buf,10);
+    iot.publishMsg("temp",buf);
+    // Convert humidity value messages to strings and send to the MQTT server
+    String(h).toCharArray(buf,10);
+    iot.publishMsg("hum",buf);
+  }
+}
+</code>

en/iot/examples/smartventilator.1525417591.txt.gz · Last modified: 2020/07/20 09:00 (external edit)