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LED_temp_indicator

+
+#include <ArduinoBLE.h>
+
+BLEService ledService("19B10000-E8F2-537E-4F6C-D104768A1214"); // BLE led service
+
+// BLE LED Switch Characteristic Uuid
+BLEByteCharacteristic switchCharacteristic("19B10001-E8F2-537E-4F6C-D104768A1214", BLERead | BLEWrite);
+
+const int ledPin = LED_BUILTIN; // pin to use for the LED
+
+void setup() {
+  Serial.begin(9600);
+  while (!Serial);
+
+  // set LED pin to output mode
+  pinMode(ledPin, OUTPUT);
+
+  // begin initialization
+  if (!BLE.begin()) {
+    Serial.println("starting Bluetooth® Low Energy module failed!");
+
+    while (1);
+  }
+
+  // set advertised local name and service UUID:
+  BLE.setLocalName("LED");
+  BLE.setAdvertisedService(ledService);
+
+  // add the characteristic to the service
+  ledService.addCharacteristic(switchCharacteristic);
+
+  // add service
+  BLE.addService(ledService);
+
+  // set the initial value for the characeristic:
+  switchCharacteristic.writeValue(0);
+
+  // start advertising
+  BLE.advertise();
+
+}
+
+void loop() {
+  //listen for ble connections
+  BLEDevice central = BLE.central();
+
+  // if a central is connected to peripheral:
+  if (central) {
+    Serial.print("Connected to central: ");
+
+    // while the central is still connected to peripheral:
+    while (central.connected()) {
+      if (switchCharacteristic.written()) {
+        if (switchCharacteristic.value() > 5) {  //target temp 5 degrees C
+          Serial.println("Not target temp");
+          digitalWrite(8,LOW);
+          digitalWrite(2, HIGH);
+        } else {                            
+          Serial.println(F("target temp achieved"));
+          digitalWrite(2,LOW);
+          digitalWrite(8,HIGH);
+        }
+      }
+    }
+
+  }
+}