Merge pull request #24 from shramik49/master

Create SendDataOnTrigger.ino

Author: jburhenn

examples/Basics/SendDataOnTrigger/SendDataOnTrigger.ino

@@ -0,0 +1,56 @@
+/*
+  This example is to be used when using Cayenne triggers. 
+  The CayenneMQTT Library is required to run this sketch. If you have not already done so you can install it from the Arduino IDE Library Manager.
+  Steps:
+  1. Set the trigger and threshold values in the sketch below.
+  2. Set the Cayenne authentication info to match the authentication info from the Dashboard.
+  3. Compile and upload the sketch.
+  4. Two temporary widget (DATA_CHANNEL and TRIGGER_CHANNEL) will be automatically generated in the Cayenne Dashboard. To make the widget permanent click the plus sign on the widget.
+  5. Add trigger on your cayenne dashboard for the TRIGGER_CHANNEL widget when it becomes 1.
+*/
+
+//#define CAYENNE_DEBUG
+#define CAYENNE_PRINT Serial
+#include <CayenneMQTTEthernet.h> // Change this to use a different communication device. See Communications examples.
+
+// Cayenne authentication info. This should be obtained from the Cayenne Dashboard.
+char username[] = "MQTT_USERNAME";
+char password[] = "MQTT_PASSWORD";
+char clientID[] = "CLIENT_ID";
+
+#define DATA_CHANNEL 0 //Virtual channel for publishing sensor data.
+#define TRIGGER_CHANNEL 1 //Virtual channel for publishing the trigger value.
+#define THRESHOLD 200 //Threshold for the trigger.
+bool sendBelowThreshold = true; //Set to true if the trigger should happen when the data value is below the threshold, 
+                                //false if it should happen when the data value is above or equal to the threshold.
+bool crossedThreshold = false;
+
+void setup() {
+  Serial.begin(9600);
+  Cayenne.begin(username, password, clientID);
+}
+
+void sendTriggerValue(int channel, int value, int threshold, bool sendBelowThreshold) {
+  if (((value >= threshold) && !sendBelowThreshold) || ((value < threshold) && sendBelowThreshold)) {
+    if (!crossedThreshold) {
+      Cayenne.virtualWrite(channel, 1, "digital_sensor", "d"); //set trigger two-state widget to 1 
+      crossedThreshold = true;
+    }
+  }
+  else
+  {
+    Cayenne.virtualWrite(channel, 0, "digital_sensor", "d"); //set trigger two-state widget to 0
+    crossedThreshold = false;
+  }
+}
+
+void loop() {
+  Cayenne.loop();
+}
+
+CAYENNE_OUT_DEFAULT()
+{
+  int sensor_value = analogRead(A0); 
+  sendTriggerValue(TRIGGER_CHANNEL, sensor_value, THRESHOLD, sendBelowThreshold);
+  Cayenne.virtualWrite(DATA_CHANNEL, sensor_value , "analog_sensor", "null"); //widget to display sensor data.
+}