diff --git a/app/src/main/java/com/example/greenwatch/viewmodels/AccelerometerViewModel.java b/app/src/main/java/com/example/greenwatch/viewmodels/AccelerometerViewModel.java
index 93e42ef..14bec64 100644
--- a/app/src/main/java/com/example/greenwatch/viewmodels/AccelerometerViewModel.java
+++ b/app/src/main/java/com/example/greenwatch/viewmodels/AccelerometerViewModel.java
@@ -12,7 +12,7 @@ import java.util.ArrayList;
 import java.util.Date;
 import java.util.List;
 
-public class AccelerometerViewModel extends ViewModel {
+public class AccelerometerViewModel extends ViewModel implements ViewModelInterface {
 
     private MutableLiveData<List<Device>> mDeviceList;
     private MutableLiveData<Boolean> mMovementDetected = new MutableLiveData<>();
@@ -26,6 +26,7 @@ public class AccelerometerViewModel extends ViewModel {
     float thresholdValue;
     boolean startMeasuring;
 
+    @Override
     public void init() {
         if (mDeviceList == null) {
             mDeviceRepository = DeviceRepository.getInstance();
@@ -89,58 +90,72 @@ public class AccelerometerViewModel extends ViewModel {
         return mMovementDetected;
     }
 
+    @Override
     public LiveData<List<Device>> getConnectedDeviceList() {
         return mDeviceList;
     }
 
+    @Override
     public LiveData<List<Device>> getAlarmHistoryList() {
         return mAlarmHistoryList;
     }
 
+    @Override
     public void updateDevice(String deviceID, String timeStamp, boolean sensorStatus, String sensorType, int sensorMassage) {
         mDeviceRepository.updateDevice(deviceID, timeStamp, sensorStatus, sensorType, sensorMassage);
     }
 
+    @Override
     public void setTimeStamp(String deviceID, String timeStamp) {
         mDeviceRepository.setTimeStamp(deviceID, timeStamp);
     }
 
+    @Override
     public String getTimeStamp(String deviceID) {
         return mDeviceRepository.getTimeStamp(deviceID);
     }
 
+    @Override
     public void setDeviceID(String deviceID, String newDeviceID) {
         mDeviceRepository.setDeviceID(deviceID, newDeviceID);
     }
 
+    @Override
     public String getDeviceID(String deviceID) {
         return mDeviceRepository.getDeviceID(deviceID);
     }
 
+    @Override
     public void setSensorStatus(String deviceID, boolean sensorStatus) {
         mDeviceRepository.setSensorStatus(deviceID, sensorStatus);
     }
 
+    @Override
     public boolean getSensorStatus(String deviceID) {
         return mDeviceRepository.getSensorStatus(deviceID);
     }
 
+    @Override
     public void setSensorType(String deviceID, String sensorType) {
         mDeviceRepository.setSensorType(deviceID, sensorType);
     }
 
+    @Override
     public String getSensorType(String deviceID) {
         return mDeviceRepository.getSensorType(deviceID);
     }
 
+    @Override
     public void setSensorMassage(String deviceID, int sensorMessage) {
         mDeviceRepository.setSensorMassage(deviceID, sensorMessage);
     }
 
+    @Override
     public int getSensorMassage(String deviceID) {
         return mDeviceRepository.getSensorMassage(deviceID);
     }
 
+    @Override
     public String getLocalDeviceUUID() {
         return mDeviceRepository.getLocalDeviceUUID();
     }
diff --git a/app/src/main/java/com/example/greenwatch/viewmodels/MainActivityViewModel.java b/app/src/main/java/com/example/greenwatch/viewmodels/MainActivityViewModel.java
index 84b2e9f..0405d93 100644
--- a/app/src/main/java/com/example/greenwatch/viewmodels/MainActivityViewModel.java
+++ b/app/src/main/java/com/example/greenwatch/viewmodels/MainActivityViewModel.java
@@ -10,13 +10,13 @@ import com.example.greenwatch.repositories.DeviceRepository;
 
 import java.util.List;
 
-public class MainActivityViewModel extends ViewModel {
+public class MainActivityViewModel extends ViewModel implements ViewModelInterface {
 
     private MutableLiveData<List<Device>> mDeviceList;
     private MutableLiveData<List<Device>> mAlarmHistoryList;
     private DeviceRepository mDeviceRepository;
 
-
+    @Override
     public void init() {
         WiFiCommunication mWiFiCommunication;
         if(mDeviceList != null) {
@@ -33,58 +33,72 @@ public class MainActivityViewModel extends ViewModel {
         mAlarmHistoryList = mDeviceRepository.getAlarmHistoryDeviceList();
     }
 
+    @Override
     public LiveData<List<Device>> getConnectedDeviceList() {
         return mDeviceList;
     }
 
+    @Override
     public LiveData<List<Device>> getAlarmHistoryList() {
         return mAlarmHistoryList;
     }
 
+    @Override
     public void updateDevice(String deviceID, String timeStamp, boolean sensorStatus, String sensorType, int sensorMassage) {
         mDeviceRepository.updateDevice(deviceID, timeStamp, sensorStatus, sensorType, sensorMassage);
     }
 
+    @Override
     public void setTimeStamp(String deviceID, String timeStamp) {
         mDeviceRepository.setTimeStamp(deviceID, timeStamp);
     }
 
+    @Override
     public String getTimeStamp(String deviceID) {
         return mDeviceRepository.getTimeStamp(deviceID);
     }
 
+    @Override
     public void setDeviceID(String deviceID, String newDeviceID) {
         mDeviceRepository.setDeviceID(deviceID, newDeviceID);
     }
 
+    @Override
     public String getDeviceID(String deviceID) {
         return mDeviceRepository.getDeviceID(deviceID);
     }
 
+    @Override
     public void setSensorStatus(String deviceID, boolean sensorStatus) {
         mDeviceRepository.setSensorStatus(deviceID, sensorStatus);
     }
 
+    @Override
     public boolean getSensorStatus(String deviceID) {
         return mDeviceRepository.getSensorStatus(deviceID);
     }
 
+    @Override
     public void setSensorType(String deviceID, String sensorType) {
         mDeviceRepository.setSensorType(deviceID, sensorType);
     }
 
+    @Override
     public String getSensorType(String deviceID) {
         return mDeviceRepository.getSensorType(deviceID);
     }
 
+    @Override
     public void setSensorMassage(String deviceID, int sensorMessage) {
         mDeviceRepository.setSensorMassage(deviceID, sensorMessage);
     }
 
+    @Override
     public int getSensorMassage(String deviceID) {
         return mDeviceRepository.getSensorMassage(deviceID);
     }
 
+    @Override
     public String getLocalDeviceUUID() {
         return mDeviceRepository.getLocalDeviceUUID();
     }
diff --git a/app/src/main/java/com/example/greenwatch/viewmodels/ViewModelInterface.java b/app/src/main/java/com/example/greenwatch/viewmodels/ViewModelInterface.java
new file mode 100644
index 0000000..45c6839
--- /dev/null
+++ b/app/src/main/java/com/example/greenwatch/viewmodels/ViewModelInterface.java
@@ -0,0 +1,25 @@
+package com.example.greenwatch.viewmodels;
+
+import androidx.lifecycle.LiveData;
+
+import com.example.greenwatch.models.Device;
+
+import java.util.List;
+
+public interface ViewModelInterface {
+    void init();
+    LiveData<List<Device>> getConnectedDeviceList();
+    LiveData<List<Device>> getAlarmHistoryList();
+    void updateDevice(String deviceID, String timeStamp, boolean sensorStatus, String sensorType, int sensorMassage);
+    void setTimeStamp(String deviceID, String timeStamp);
+    String getTimeStamp(String deviceID);
+    void setDeviceID(String deviceID, String newDeviceID);
+    String getDeviceID(String deviceID);
+    void setSensorStatus(String deviceID, boolean sensorStatus);
+    boolean getSensorStatus(String deviceID);
+    void setSensorType(String deviceID, String sensorType);
+    String getSensorType(String deviceID);
+    void setSensorMassage(String deviceID, int sensorMessage);
+    int getSensorMassage(String deviceID);
+    String getLocalDeviceUUID();
+}