diff --git a/.idea/misc.xml b/.idea/misc.xml
index 860da66..9a43771 100644
--- a/.idea/misc.xml
+++ b/.idea/misc.xml
@@ -1,5 +1,12 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
+  <component name="DesignSurface">
+    <option name="filePathToZoomLevelMap">
+      <map>
+        <entry key="app/src/main/res/layout/activity_main.xml" value="0.33" />
+      </map>
+    </option>
+  </component>
   <component name="ProjectRootManager" version="2" languageLevel="JDK_11" default="true" project-jdk-name="1.8" project-jdk-type="JavaSDK">
     <output url="file://$PROJECT_DIR$/build/classes" />
   </component>
diff --git a/app/src/main/java/com/example/co2sense_app/BLEDevice.java b/app/src/main/java/com/example/co2sense_app/BLEDevice.java
index 48bbcc9..5c48030 100644
--- a/app/src/main/java/com/example/co2sense_app/BLEDevice.java
+++ b/app/src/main/java/com/example/co2sense_app/BLEDevice.java
@@ -7,6 +7,7 @@ import android.bluetooth.BluetoothAdapter;
 import android.bluetooth.BluetoothDevice;
 import android.bluetooth.BluetoothGatt;
 import android.bluetooth.BluetoothGattCallback;
+import android.bluetooth.BluetoothGattCharacteristic;
 import android.bluetooth.BluetoothManager;
 import android.bluetooth.BluetoothProfile;
 import android.companion.AssociationRequest;
@@ -26,9 +27,10 @@ import androidx.annotation.RequiresApi;
 import androidx.core.app.ActivityCompat;
 import androidx.core.content.ContextCompat;
 
+import java.nio.ByteBuffer;
 import java.util.NoSuchElementException;
 
-public class BLEDevice {
+public abstract class BLEDevice {
     private static final int REQUEST_BT_PERMISSION = 16535;
     private static final int REQUEST_ENABLE_BT = 16536;
     private static final int SELECT_DEVICE_REQUEST_CODE = 16537;
@@ -37,7 +39,7 @@ public class BLEDevice {
     private final Activity activity;
     private boolean startPairingOnBTStart;
 
-    private BluetoothGatt bluetoothGatt;
+    protected BluetoothGatt bluetoothGatt;
     private BluetoothDevice device;
     private final ActivityResultLauncher<String> requestPermissionLauncher;
 
@@ -48,6 +50,7 @@ public class BLEDevice {
     }
 
     public void startBT() {
+        Log.d("bt", "startBT");
         Context context = activity.getApplicationContext();
         BluetoothManager bluetoothManager = ContextCompat.getSystemService(context, BluetoothManager.class);
         if (bluetoothManager == null)
@@ -69,6 +72,7 @@ public class BLEDevice {
     }
 
     protected void pair() {
+        Log.d("bt", "pair");
         BluetoothDeviceFilter deviceFilter = new BluetoothDeviceFilter.Builder()
                 //.setNamePattern(Pattern.compile("My device"))
                 //.addServiceUuid(new ParcelUuid(new UUID(0x123abcL, -1L)), null)
@@ -106,15 +110,33 @@ public class BLEDevice {
             return;
         }*/
         Log.d("bt", device.toString());
+        BLEDevice mainClass = this;
         bluetoothGatt = device.connectGatt(activity, false, new BluetoothGattCallback() {
             @Override
             public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
                 if (newState == BluetoothProfile.STATE_CONNECTED) {
                     Log.d("bt", "connected");
+                    bluetoothGatt.discoverServices();
                 } else if (newState == BluetoothProfile.STATE_DISCONNECTED) {
                     Log.d("bt", "disconnected");
                 }
             }
+
+            @Override
+            public void onServicesDiscovered(BluetoothGatt gatt, int status) {
+                if (status == BluetoothGatt.GATT_SUCCESS) {
+                    Log.d("bt", "onServicesDiscovered: finished");
+                    mainClass.onServicesDiscovered();
+                } else {
+                    Log.w("bt", "onServicesDiscovered received: " + status);
+                }
+            }
+
+            @Override
+            public void onCharacteristicChanged(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) {
+                super.onCharacteristicChanged(gatt, characteristic);
+                Log.d("bt", "onCharacteristicChanged: "+ ByteBuffer.wrap(characteristic.getValue()).getShort());
+            }
         });
     }
 
@@ -147,4 +169,8 @@ public class BLEDevice {
     public void startPairingOnBTStart(boolean status) {
         startPairingOnBTStart = status;
     }
+
+    protected void onServicesDiscovered(){
+
+    }
 }
diff --git a/app/src/main/java/com/example/co2sense_app/CO2Sensor.java b/app/src/main/java/com/example/co2sense_app/CO2Sensor.java
index d02dbbd..6925477 100644
--- a/app/src/main/java/com/example/co2sense_app/CO2Sensor.java
+++ b/app/src/main/java/com/example/co2sense_app/CO2Sensor.java
@@ -1,13 +1,51 @@
 package com.example.co2sense_app;
 
+import android.Manifest;
+import android.annotation.SuppressLint;
 import android.app.Activity;
+import android.bluetooth.BluetoothAssignedNumbers;
+import android.bluetooth.BluetoothGatt;
+import android.bluetooth.BluetoothGattCharacteristic;
+import android.bluetooth.BluetoothGattDescriptor;
+import android.bluetooth.BluetoothGattService;
+import android.content.pm.PackageManager;
 import android.os.Build;
+import android.util.Log;
 
 import androidx.annotation.RequiresApi;
+import androidx.core.app.ActivityCompat;
+
+import java.util.List;
+import java.util.UUID;
 
 public class CO2Sensor extends BLEDevice {
+    private int co2, temp, hum;
+
+    public final UUID ENVIRONMENTAL_SENSING_UUID = UUID.fromString("0000181a-0000-1000-8000-00805f9b34fb");
+    public final UUID CHAR_CO2_UUID = UUID.fromString("00000C39-0000-1000-8000-00805f9b34fb");
+    public final UUID CHAR_TEMP_UUID = UUID.fromString("00002A6E-0000-1000-8000-00805f9b34fb");
+    public final UUID CHAR_HUM_UUID = UUID.fromString("00002A6F-0000-1000-8000-00805f9b34fb");
+    public final UUID DESCR_CCC_UUID = UUID.fromString("00002902-0000-1000-8000-00805f9b34fb");
+
+
     @RequiresApi(api = Build.VERSION_CODES.S)
     CO2Sensor(Activity activity) {
         super(activity);
     }
+
+    @Override
+    protected void onServicesDiscovered() {
+        super.onServicesDiscovered();
+        enableNotifications(bluetoothGatt);
+    }
+
+    @SuppressLint("MissingPermission")
+    private void enableNotifications(BluetoothGatt bluetoothGatt) {
+        BluetoothGattService ES = bluetoothGatt.getService(ENVIRONMENTAL_SENSING_UUID);
+        BluetoothGattCharacteristic CO2Char = ES.getCharacteristic(CHAR_CO2_UUID);
+        BluetoothGattDescriptor CO2Descr = CO2Char.getDescriptor(DESCR_CCC_UUID);
+        CO2Descr.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
+        bluetoothGatt.setCharacteristicNotification(CO2Char, true);
+        bluetoothGatt.writeDescriptor(CO2Descr);
+    }
 }
diff --git a/app/src/main/java/com/example/co2sense_app/MainActivity.java b/app/src/main/java/com/example/co2sense_app/MainActivity.java
index 53e8fff..86f2056 100644
--- a/app/src/main/java/com/example/co2sense_app/MainActivity.java
+++ b/app/src/main/java/com/example/co2sense_app/MainActivity.java
@@ -3,29 +3,36 @@ package com.example.co2sense_app;
 import androidx.annotation.Nullable;
 import androidx.annotation.RequiresApi;
 import androidx.appcompat.app.AppCompatActivity;
+import androidx.constraintlayout.widget.ConstraintLayout;
 
 import android.content.Intent;
 import android.os.Build;
 import android.os.Bundle;
+import android.view.View;
 
 public class MainActivity extends AppCompatActivity {
-    BLEDevice sensor;
+    CO2Sensor sensor;
 
+    @RequiresApi(api = Build.VERSION_CODES.S)
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
+
+        sensor = new CO2Sensor(this);
+        sensor.startPairingOnBTStart(true);
+
+        ConstraintLayout mainLayout = findViewById(R.id.mainLayout);
+        mainLayout.setOnClickListener(v -> {
+            sensor.startBT();
+            sensor.pair();
+        });
     }
 
-    @RequiresApi(api = Build.VERSION_CODES.S)
     @Override
-    protected void onStart() {
-        super.onStart();
-
-        sensor = new BLEDevice(this);
-        sensor.startPairingOnBTStart(true);
-        sensor.startBT();
-        sensor.pair();
+    protected void onDestroy() {
+        super.onDestroy();
+        sensor.disconnect();
     }
 
     @RequiresApi(api = Build.VERSION_CODES.S)
diff --git a/app/src/main/res/layout/activity_main.xml b/app/src/main/res/layout/activity_main.xml
index 4fc2444..6540f57 100644
--- a/app/src/main/res/layout/activity_main.xml
+++ b/app/src/main/res/layout/activity_main.xml
@@ -2,17 +2,7 @@
 <androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto"
     xmlns:tools="http://schemas.android.com/tools"
+    android:id="@+id/mainLayout"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
-    tools:context=".MainActivity">
-
-    <TextView
-        android:layout_width="wrap_content"
-        android:layout_height="wrap_content"
-        android:text="Hello World!"
-        app:layout_constraintBottom_toBottomOf="parent"
-        app:layout_constraintLeft_toLeftOf="parent"
-        app:layout_constraintRight_toRightOf="parent"
-        app:layout_constraintTop_toTopOf="parent" />
-
-</androidx.constraintlayout.widget.ConstraintLayout>
\ No newline at end of file
+    tools:context=".MainActivity"/>
\ No newline at end of file