diff --git a/app/src/main/res/layout-land/fragment_mainscreen.xml b/app/src/main/res/layout-land/fragment_mainscreen.xml
index 42cc704c24288257bfc0a035ec20009210443209..d88978f6a5956f856c2d6d968b80fbefba2d4de2 100644
--- a/app/src/main/res/layout-land/fragment_mainscreen.xml
+++ b/app/src/main/res/layout-land/fragment_mainscreen.xml
@@ -1,53 +1,53 @@
-<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
-    android:id="@+id/main_screen_buttons"
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
-    android:layout_height="match_parent">
+    android:layout_height="match_parent"
+    android:orientation="horizontal" >
+    <LinearLayout
+        android:layout_width="0dp"
+        android:layout_height="match_parent"
+        android:layout_weight="1"
+        android:gravity="center_vertical|center_horizontal"
+        android:orientation="vertical">
+        <ImageButton
+            android:id="@+id/imageButtonAbout"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:onClick="activityStart"
+            android:src="@drawable/about_icon"
+            android:background="@null"
+            android:contentDescription="@string/aboutButtonMain"/>
+        <ImageButton
+            android:id="@+id/imageButtonTakeSample"
+            android:layout_width="wrap_content"
+            android:layout_marginTop="38dp"
+            android:layout_height="wrap_content"
+            android:background="@null"
+            android:onClick="activityStart"
+            android:contentDescription="@string/takeSampleButton"
+            android:src="@drawable/sampling_icon"/>
+    </LinearLayout>
+    <LinearLayout
+        android:layout_width="0dp"
+        android:layout_height="match_parent"
+        android:layout_weight="1"
+        android:gravity="center_vertical|center_horizontal"
+        android:orientation="vertical" >
+        <ImageButton
+            android:id="@+id/imageButtonSettings"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:onClick="activityStart"
+            android:src="@drawable/settings_icon"
+            android:background="@null"
+            android:contentDescription="@string/settingsButtonMain"/>
+        <ImageButton
+            android:id="@+id/imageButtonLabNotebook"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:background="@null"
+            android:onClick="activityStart"
+            android:contentDescription="@string/labNotebookButtonMain"
+            android:src="@drawable/lab_notebook_icon"/>
+    </LinearLayout>
 
-    <ImageButton
-        android:id="@+id/imageButtonAbout"
-        android:layout_width="wrap_content"
-        android:layout_height="wrap_content"
-        android:onClick="activityStart"
-        android:src="@drawable/about_icon"
-        android:background="@null"
-        android:contentDescription="@string/aboutButtonMain"
-        android:layout_marginEnd="299dp"
-        android:layout_above="@+id/imageButtonTakeSample"
-        android:layout_toStartOf="@+id/imageButtonSettings" />
-
-    <ImageButton
-        android:id="@+id/imageButtonSettings"
-        android:layout_width="wrap_content"
-        android:layout_height="wrap_content"
-        android:onClick="activityStart"
-        android:src="@drawable/settings_icon"
-        android:background="@null"
-        android:contentDescription="@string/settingsButtonMain"
-        android:layout_marginEnd="177dp"
-        android:layout_alignTop="@+id/imageButtonAbout"
-        android:layout_alignParentEnd="true" />
-
-    <ImageButton
-        android:id="@+id/imageButtonTakeSample"
-        android:layout_width="wrap_content"
-        android:layout_height="wrap_content"
-        android:background="@null"
-        android:onClick="activityStart"
-        android:contentDescription="@string/takeSampleButton"
-        android:src="@drawable/sampling_icon"
-        android:layout_alignBottom="@+id/imageButtonLabNotebook"
-        android:layout_toEndOf="@+id/imageButtonAbout" />
-
-    <ImageButton
-        android:id="@+id/imageButtonLabNotebook"
-        android:layout_width="wrap_content"
-        android:layout_height="wrap_content"
-        android:background="@null"
-        android:onClick="activityStart"
-        android:contentDescription="@string/labNotebookButtonMain"
-        android:src="@drawable/lab_notebook_icon"
-        android:layout_marginBottom="96dp"
-        android:layout_alignParentBottom="true"
-        android:layout_alignEnd="@+id/imageButtonAbout" />
-
-</RelativeLayout>
\ No newline at end of file
+</LinearLayout>
\ No newline at end of file
diff --git a/app/src/main/res/layout-land/fragment_sensorscreen.xml b/app/src/main/res/layout-land/fragment_sensorscreen.xml
index 28cd27b958deb52dacbd278fbe4d7820e6ac09ef..41c39015946f165a01e1f5861f175427aeb916ca 100644
--- a/app/src/main/res/layout-land/fragment_sensorscreen.xml
+++ b/app/src/main/res/layout-land/fragment_sensorscreen.xml
@@ -1,45 +1,49 @@
 <?xml version="1.0" encoding="utf-8"?>
-<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
-    android:id="@+id/sensor_sample_buttons"
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
-    android:background="@drawable/take_a_sample_landscape"
-    android:focusableInTouchMode="true" >
+    android:orientation="horizontal" >
 
-    <ImageButton
-        android:layout_width="wrap_content"
-        android:layout_height="wrap_content"
-        android:id="@+id/imageButtonBuiltIn"
-        android:src="@drawable/builtin_sensors_icon"
-        android:contentDescription="@string/builtinSensors"
-        android:background="@null"
-        android:onClick="startSampleActivity"
-        android:layout_marginTop="74dp"
-        android:layout_marginStart="192dp"
-        android:layout_alignParentTop="true"
-        android:layout_alignParentStart="true" />
+    <LinearLayout
+        android:layout_width="0dp"
+        android:layout_height="match_parent"
+        android:layout_weight="1"
+        android:gravity="center_vertical|center_horizontal"
+        android:orientation="vertical">
 
-    <ImageButton
-        android:layout_width="wrap_content"
-        android:layout_height="wrap_content"
-        android:id="@+id/imageButtonBluetooth"
-        android:src="@drawable/bluetooth_devices"
-        android:contentDescription="@string/bluetoothSensor"
-        android:background="@null"
-        android:onClick="startSampleActivity"
-        android:layout_alignTop="@+id/imageButtonBuiltIn"
-        android:layout_alignParentEnd="true"
-        android:layout_marginEnd="248dp" />
+        <ImageButton
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:id="@+id/imageButtonBuiltIn"
+            android:src="@drawable/builtin_sensors_icon"
+            android:contentDescription="@string/builtinSensors"
+            android:background="@null"
+            android:onClick="startSampleActivity" />
 
-    <ImageButton
-        android:layout_width="wrap_content"
-        android:layout_height="wrap_content"
-        android:id="@+id/imageButtonDbActions"
-        android:src="@drawable/database_actions_icon"
-        android:contentDescription="Database Actions"
-        android:background="@null"
-        android:onClick="startSampleActivity"
-        android:layout_below="@+id/imageButtonBuiltIn"
-        android:layout_toEndOf="@+id/imageButtonBuiltIn"
-        android:layout_marginTop="73dp" />
-</RelativeLayout>
\ No newline at end of file
+        <ImageButton
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:id="@+id/imageButtonBluetooth"
+            android:src="@drawable/bluetooth_devices"
+            android:contentDescription="@string/bluetoothSensor"
+            android:background="@null"
+            android:onClick="startSampleActivity"/>
+    </LinearLayout>
+    <LinearLayout
+        android:layout_width="0dp"
+        android:layout_height="match_parent"
+        android:layout_weight="1"
+        android:gravity="center_vertical|center_horizontal"
+        android:orientation="vertical" >
+
+        <ImageButton
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:id="@+id/imageButtonDbActions"
+            android:src="@drawable/database_actions_icon"
+            android:contentDescription="@string/databaseActions"
+            android:background="@null"
+            android:onClick="startSampleActivity" />
+    </LinearLayout>
+
+</LinearLayout>
\ No newline at end of file
diff --git a/app/src/main/res/layout/fragment_labnotescreen.xml b/app/src/main/res/layout/fragment_labnotescreen.xml
index 2639c9f806276fed4d3af610e31cce841e954fd3..9661dbcbe6fadee31c20b87f5623d5fc4b35736a 100644
--- a/app/src/main/res/layout/fragment_labnotescreen.xml
+++ b/app/src/main/res/layout/fragment_labnotescreen.xml
@@ -1,45 +1,44 @@
 <?xml version="1.0" encoding="utf-8"?>
-<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
-    android:id="@+id/lab_note_screen"
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
-    android:focusableInTouchMode="true" >
-
-    <ImageButton
-        android:id="@+id/imageButtonNotePad"
-        android:layout_width="wrap_content"
-        android:layout_height="wrap_content"
-        android:layout_marginRight="53dp"
-        android:onClick="labNotebookStart"
-        android:background="@null"
-        android:contentDescription="@string/notepadButtonMain"
-        android:src="@drawable/note_pad_icon"
-        android:layout_alignTop="@+id/imageButtonLabProtocols"
-        android:layout_alignParentStart="true"
-        android:layout_marginStart="103dp" />
-
-    <ImageButton
-        android:id="@id/imageButtonLabProtocols"
-        android:layout_width="wrap_content"
-        android:layout_height="wrap_content"
-        android:onClick="labNotebookStart"
-        android:background="@null"
-        android:contentDescription="@string/labButtonMain"
-        android:src="@drawable/lab_protocols_icon"
-        android:layout_centerVertical="true"
-        android:layout_toEndOf="@+id/imageButtonNotePad"
-        android:layout_marginStart="61dp" />
-
-    <ImageButton
-        android:id="@+id/imageButtonDrive"
-        android:layout_width="wrap_content"
-        android:layout_height="wrap_content"
-        android:onClick="labNotebookStart"
-        android:background="@null"
-        android:contentDescription="Connect to Google Drive"
-        android:src="@drawable/drive"
-        android:layout_above="@id/imageButtonLabProtocols"
-        android:layout_centerHorizontal="true"
-        android:layout_marginBottom="76dp" />
-
-</RelativeLayout>
\ No newline at end of file
+    android:orientation="horizontal" >
+    <LinearLayout
+        android:layout_width="0dp"
+        android:layout_height="match_parent"
+        android:layout_weight="1"
+        android:gravity="center_vertical|center_horizontal"
+        android:orientation="vertical">
+        <ImageButton
+            android:id="@+id/imageButtonNotePad"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:onClick="labNotebookStart"
+            android:background="@null"
+            android:contentDescription="@string/notepadButtonMain"
+            android:src="@drawable/note_pad_icon" />
+        <ImageButton
+            android:id="@+id/imageButtonLabProtocols"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:onClick="labNotebookStart"
+            android:background="@null"
+            android:contentDescription="@string/labButtonMain"
+            android:src="@drawable/lab_protocols_icon"/>
+    </LinearLayout>
+    <LinearLayout
+        android:layout_width="0dp"
+        android:layout_height="match_parent"
+        android:layout_weight="1"
+        android:gravity="center_vertical|center_horizontal"
+        android:orientation="vertical" >
+        <ImageButton
+            android:id="@+id/imageButtonDrive"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:onClick="labNotebookStart"
+            android:background="@null"
+            android:contentDescription="Connect to Google Drive"
+            android:src="@drawable/drive" />
+    </LinearLayout>
+</LinearLayout>
\ No newline at end of file
diff --git a/app/src/main/res/layout/fragment_mainscreen.xml b/app/src/main/res/layout/fragment_mainscreen.xml
index 0afb50544ede22c29488cd22e451f23a42e1794b..d88978f6a5956f856c2d6d968b80fbefba2d4de2 100644
--- a/app/src/main/res/layout/fragment_mainscreen.xml
+++ b/app/src/main/res/layout/fragment_mainscreen.xml
@@ -1,53 +1,53 @@
-<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
-    android:id="@+id/main_screen_buttons"
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
-    android:layout_height="match_parent">
+    android:layout_height="match_parent"
+    android:orientation="horizontal" >
+    <LinearLayout
+        android:layout_width="0dp"
+        android:layout_height="match_parent"
+        android:layout_weight="1"
+        android:gravity="center_vertical|center_horizontal"
+        android:orientation="vertical">
+        <ImageButton
+            android:id="@+id/imageButtonAbout"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:onClick="activityStart"
+            android:src="@drawable/about_icon"
+            android:background="@null"
+            android:contentDescription="@string/aboutButtonMain"/>
+        <ImageButton
+            android:id="@+id/imageButtonTakeSample"
+            android:layout_width="wrap_content"
+            android:layout_marginTop="38dp"
+            android:layout_height="wrap_content"
+            android:background="@null"
+            android:onClick="activityStart"
+            android:contentDescription="@string/takeSampleButton"
+            android:src="@drawable/sampling_icon"/>
+    </LinearLayout>
+    <LinearLayout
+        android:layout_width="0dp"
+        android:layout_height="match_parent"
+        android:layout_weight="1"
+        android:gravity="center_vertical|center_horizontal"
+        android:orientation="vertical" >
+        <ImageButton
+            android:id="@+id/imageButtonSettings"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:onClick="activityStart"
+            android:src="@drawable/settings_icon"
+            android:background="@null"
+            android:contentDescription="@string/settingsButtonMain"/>
+        <ImageButton
+            android:id="@+id/imageButtonLabNotebook"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:background="@null"
+            android:onClick="activityStart"
+            android:contentDescription="@string/labNotebookButtonMain"
+            android:src="@drawable/lab_notebook_icon"/>
+    </LinearLayout>
 
-    <ImageButton
-        android:id="@+id/imageButtonAbout"
-        android:layout_width="wrap_content"
-        android:layout_height="wrap_content"
-        android:onClick="activityStart"
-        android:src="@drawable/about_icon"
-        android:background="@null"
-        android:contentDescription="@string/aboutButtonMain"
-        android:layout_marginBottom="57dp"
-        android:layout_marginEnd="79dp"
-        android:layout_above="@+id/imageButtonTakeSample"
-        android:layout_toStartOf="@+id/imageButtonSettings" />
-
-    <ImageButton
-        android:id="@+id/imageButtonSettings"
-        android:layout_width="wrap_content"
-        android:layout_height="wrap_content"
-        android:onClick="activityStart"
-        android:src="@drawable/settings_icon"
-        android:background="@null"
-        android:contentDescription="@string/settingsButtonMain"
-        android:layout_marginEnd="103dp"
-        android:layout_alignBottom="@+id/imageButtonAbout"
-        android:layout_alignParentEnd="true" />
-
-    <ImageButton
-        android:id="@+id/imageButtonTakeSample"
-        android:layout_width="wrap_content"
-        android:layout_height="wrap_content"
-        android:background="@null"
-        android:onClick="activityStart"
-        android:contentDescription="@string/takeSampleButton"
-        android:src="@drawable/sampling_icon"
-        android:layout_alignBottom="@+id/imageButtonLabNotebook"
-        android:layout_toEndOf="@+id/imageButtonAbout" />
-
-    <ImageButton
-        android:id="@+id/imageButtonLabNotebook"
-        android:layout_width="wrap_content"
-        android:layout_height="wrap_content"
-        android:background="@null"
-        android:onClick="activityStart"
-        android:contentDescription="@string/labNotebookButtonMain"
-        android:src="@drawable/lab_notebook_icon"
-        android:layout_centerVertical="true"
-        android:layout_alignEnd="@+id/imageButtonAbout" />
-
-</RelativeLayout>
\ No newline at end of file
+</LinearLayout>
\ No newline at end of file
diff --git a/app/src/main/res/layout/fragment_sensorscreen.xml b/app/src/main/res/layout/fragment_sensorscreen.xml
index 10cf18f313e9ef3105cde72e1b45ceda1df28979..41c39015946f165a01e1f5861f175427aeb916ca 100644
--- a/app/src/main/res/layout/fragment_sensorscreen.xml
+++ b/app/src/main/res/layout/fragment_sensorscreen.xml
@@ -1,43 +1,49 @@
 <?xml version="1.0" encoding="utf-8"?>
-<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
-    android:id="@+id/sensor_sample_buttons"
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
-    android:background="@drawable/take_a_sample_bg"
-    android:focusableInTouchMode="true" >
+    android:orientation="horizontal" >
 
-    <ImageButton
-        android:layout_width="wrap_content"
-        android:layout_height="wrap_content"
-        android:id="@+id/imageButtonBuiltIn"
-        android:src="@drawable/builtin_sensors_icon"
-        android:contentDescription="@string/builtinSensors"
-        android:background="@null"
-        android:onClick="startSampleActivity"
-        android:adjustViewBounds="false"
-        android:layout_centerVertical="true"
-        android:layout_centerHorizontal="true" />
+    <LinearLayout
+        android:layout_width="0dp"
+        android:layout_height="match_parent"
+        android:layout_weight="1"
+        android:gravity="center_vertical|center_horizontal"
+        android:orientation="vertical">
 
-    <ImageButton
-        android:layout_width="wrap_content"
-        android:layout_height="wrap_content"
-        android:id="@+id/imageButtonBluetooth"
-        android:src="@drawable/bluetooth_devices"
-        android:contentDescription="@string/bluetoothSensor"
-        android:background="@null"
-        android:onClick="startSampleActivity"
-        android:layout_alignBottom="@+id/imageButtonDbActions"
-        android:layout_toStartOf="@+id/imageButtonBuiltIn" />
+        <ImageButton
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:id="@+id/imageButtonBuiltIn"
+            android:src="@drawable/builtin_sensors_icon"
+            android:contentDescription="@string/builtinSensors"
+            android:background="@null"
+            android:onClick="startSampleActivity" />
 
-    <ImageButton
-        android:layout_width="wrap_content"
-        android:layout_height="wrap_content"
-        android:id="@+id/imageButtonDbActions"
-        android:src="@drawable/database_actions_icon"
-        android:contentDescription="@string/databaseActions"
-        android:background="@null"
-        android:onClick="startSampleActivity"
-        android:layout_above="@+id/imageButtonBuiltIn"
-        android:layout_toEndOf="@+id/imageButtonBuiltIn"
-        android:layout_marginBottom="84dp" />
-</RelativeLayout>
\ No newline at end of file
+        <ImageButton
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:id="@+id/imageButtonBluetooth"
+            android:src="@drawable/bluetooth_devices"
+            android:contentDescription="@string/bluetoothSensor"
+            android:background="@null"
+            android:onClick="startSampleActivity"/>
+    </LinearLayout>
+    <LinearLayout
+        android:layout_width="0dp"
+        android:layout_height="match_parent"
+        android:layout_weight="1"
+        android:gravity="center_vertical|center_horizontal"
+        android:orientation="vertical" >
+
+        <ImageButton
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:id="@+id/imageButtonDbActions"
+            android:src="@drawable/database_actions_icon"
+            android:contentDescription="@string/databaseActions"
+            android:background="@null"
+            android:onClick="startSampleActivity" />
+    </LinearLayout>
+
+</LinearLayout>
\ No newline at end of file