diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
index e6408bb..978a328 100644
--- a/app/src/main/AndroidManifest.xml
+++ b/app/src/main/AndroidManifest.xml
@@ -2,6 +2,11 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     package="com.example.greenwatch">
 
+    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
+    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
+    <uses-permission android:name="android.permission.RECORD_AUDIO" />
+    <uses-permission android:name="android.permission.CAMERA" />
+
     <application
         android:allowBackup="true"
         android:icon="@mipmap/ic_launcher"
diff --git a/app/src/main/java/com/example/greenwatch/MainActivity.java b/app/src/main/java/com/example/greenwatch/MainActivity.java
index 98aa213..3d9dd52 100644
--- a/app/src/main/java/com/example/greenwatch/MainActivity.java
+++ b/app/src/main/java/com/example/greenwatch/MainActivity.java
@@ -1,14 +1,351 @@
 package com.example.greenwatch;
 
-import androidx.appcompat.app.AppCompatActivity;
-
+import android.Manifest;
+import android.content.pm.PackageManager;
+import android.media.MediaCodec;
+import android.media.MediaExtractor;
+import android.media.MediaFormat;
+import android.media.MediaMuxer;
+import android.media.MediaRecorder;
 import android.os.Bundle;
+import android.os.Environment;
+import android.view.View;
+import android.widget.Button;
+import android.widget.Toast;
+import android.widget.VideoView;
+
+import androidx.appcompat.app.AppCompatActivity;
+import androidx.core.app.ActivityCompat;
+import androidx.core.content.ContextCompat;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.ByteBuffer;
 
 public class MainActivity extends AppCompatActivity {
 
+    private boolean alarm_on = false; //ToDo diese Variable durch die Alarm-Variable=true setzen und nicht über einen Button
+    private boolean alarm_off = false; //ToDo diese Variable durch die Alarm-Variable=false setzen und nicht über einen Button
+    private static final int REQUEST_PERMISSION = 200;
+    private Button button;
+    private VideoView videoView;
+    private MediaRecorder mediaRecorder;
+    private MediaRecorder audioRecorder;
+    private MediaFormat videoFormat;
+    private MediaFormat audioFormat;
+    private MediaExtractor videoExtractor;
+    private MediaExtractor audioExtractor;
+    private String videoPath;
+    private String audioPath;
+    private boolean isRecording = false;
+
+    private Thread videoThread; // Video-Thread als Instanzvariable
+    private Thread audioThread; // Audio-Thread als Instanzvariable
+
+    private static final int REQUEST_PERMISSIONS = 123;
+
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
+
+        button = findViewById(R.id.button);
+        videoView = findViewById(R.id.videoView);
+
+        button.setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View v) {
+                if (!isRecording) {
+                    if (ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.CAMERA)
+                            != PackageManager.PERMISSION_GRANTED
+                            || ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.WRITE_EXTERNAL_STORAGE)
+                            != PackageManager.PERMISSION_GRANTED
+                            || ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.RECORD_AUDIO)
+                            != PackageManager.PERMISSION_GRANTED) {
+                        ActivityCompat.requestPermissions(MainActivity.this,
+                                new String[]{Manifest.permission.CAMERA, Manifest.permission.WRITE_EXTERNAL_STORAGE, Manifest.permission.RECORD_AUDIO},
+                                REQUEST_PERMISSION);
+                    } else {
+                        alarm_on = true;
+                        onAlarmStateChanged();
+                    }
+                } else {
+                    alarm_off = true;
+                    onAlarmStateChanged();
+                }
+            }
+        });
+    }
+
+    public void onAlarmStateChanged() {
+        runOnUiThread(new Runnable() {
+            @Override
+            public void run() {
+                if (alarm_on) {
+                    alarm_on = false; //Variable zurücksetzen
+                    startRecording();
+                } else if (alarm_off) {
+                    alarm_off = false; //Variable zurücksetzen
+                    stopRecording();
+                }
+            }
+        });
+    }
+
+    private void cache(){
+        //Pfade zum Zwischenspeichern der aufgenommenen Audio und Video-Datei
+        isRecording = true;
+        String externalStorageDirectory = Environment.getExternalStorageDirectory().getAbsolutePath();
+        String dcimDirectory = externalStorageDirectory + "/DCIM";
+        videoPath = dcimDirectory + "/video.mp4";
+        audioPath = dcimDirectory + "/audio.mp3";
+    }
+
+    private void VideoThread(){
+        videoThread = new Thread(new Runnable() {
+            @Override
+            public void run() {
+                mediaRecorder = new MediaRecorder();
+                mediaRecorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);
+                mediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
+                mediaRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.DEFAULT);
+                mediaRecorder.setOutputFile(videoPath);
+                mediaRecorder.setOrientationHint(90);
+                mediaRecorder.setPreviewDisplay(videoView.getHolder().getSurface());
+
+                try {
+                    mediaRecorder.prepare();
+                    mediaRecorder.start();
+                    runOnUiThread(new Runnable() {
+                        @Override
+                        public void run() {
+                            Toast.makeText(MainActivity.this, "Videoaufzeichnung gestartet", Toast.LENGTH_SHORT).show();
+                        }
+                    });
+                } catch (IOException e) {
+                    e.printStackTrace();
+                }
+            }
+        });
+    }
+
+    private void AudioThread(){
+        audioThread = new Thread(new Runnable() {
+            @Override
+            public void run() {
+                audioRecorder = new MediaRecorder();
+                audioRecorder.setAudioSource(MediaRecorder.AudioSource.DEFAULT);
+                audioRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
+                audioRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AAC);
+                audioRecorder.setOutputFile(audioPath);
+
+                try {
+                    audioRecorder.prepare();
+                    audioRecorder.start();
+                    runOnUiThread(new Runnable() {
+                        @Override
+                        public void run() {
+                            Toast.makeText(MainActivity.this, "Audioaufzeichnung gestartet", Toast.LENGTH_SHORT).show();
+                        }
+                    });
+                } catch (IOException e) {
+                    e.printStackTrace();
+                }
+            }
+        });
+    }
+
+    private void startRecording() {
+        cache(); //Speicherort und -namen für Audio- und Video-Datei
+
+        VideoThread(); //Videoaufzeichnungs-Thread anlegen
+        AudioThread(); //Audioaufzeichnungs-Thread anlegen
+
+        //Threads starten
+        videoThread.start();
+        audioThread.start();
+    }
+
+    private void stopVideoRecording(){
+        if (mediaRecorder != null) {
+            mediaRecorder.stop();
+            mediaRecorder.release();
+            mediaRecorder = null;
+        }
+    }
+
+    private void stopAudioRecording(){
+        if (audioRecorder != null) {
+            audioRecorder.stop();
+            audioRecorder.release();
+            audioRecorder = null;
+        }
+    }
+
+    private void waitTillThreadsStopped(){
+        try {
+            videoThread.join();
+            audioThread.join();
+        } catch (InterruptedException e) {
+            e.printStackTrace();
+        }
+    }
+
+    private void stopRecording() {
+        isRecording = false;
+        try {
+            stopVideoRecording();
+            stopAudioRecording();
+
+            runOnUiThread(new Runnable() {
+                @Override
+                public void run() {
+                    Toast.makeText(MainActivity.this, "Video- und Audioaufzeichnung beendet", Toast.LENGTH_SHORT).show();
+                }
+            });
+
+            waitTillThreadsStopped();
+            File videoFile = new File(videoPath); //Speichere das aufgenommene Video
+            File audioFile = new File(audioPath); //Speichere die aufgenommene Audio
+
+            if (videoFile.exists() && audioFile.exists()) {
+                //Wenn Video- und Audioaufzeichnung gestoppt und abgespeichert sind, beginne mit dem Mergeprozess der beiden
+                mergeVideoWithAudio();
+            } else {
+                Toast.makeText(MainActivity.this, "Dateien wurden nicht gefunden!", Toast.LENGTH_SHORT).show();
+            }
+        } catch (RuntimeException stopException) {
+            stopException.printStackTrace();
+        }
+    }
+
+    private void newMediaExtractor() {
+        videoExtractor = new MediaExtractor();
+        try {
+            videoExtractor.setDataSource(videoPath);
+            int videoTrackIndex = getTrackIndex(videoExtractor, "video/");
+            if (videoTrackIndex < 0) {
+                // Video-Track nicht gefunden
+                return;
+            }
+            videoExtractor.selectTrack(videoTrackIndex);
+            videoFormat = videoExtractor.getTrackFormat(videoTrackIndex);
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    private void newAudioExtractor() {
+        audioExtractor = new MediaExtractor();
+        try {
+            audioExtractor.setDataSource(audioPath);
+            int audioTrackIndex = getTrackIndex(audioExtractor, "audio/");
+            if (audioTrackIndex < 0) {
+                // Audio-Track nicht gefunden
+                return;
+            }
+            audioExtractor.selectTrack(audioTrackIndex);
+            audioFormat = audioExtractor.getTrackFormat(audioTrackIndex);
+
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    private void mediaExtraction(ByteBuffer buffer, int videoTrack, MediaCodec.BufferInfo bufferInfo, MediaMuxer muxer) {
+        videoExtractor.seekTo(0, MediaExtractor.SEEK_TO_CLOSEST_SYNC);
+        while (true) {
+            int sampleSize = videoExtractor.readSampleData(buffer, 0);
+            if (sampleSize < 0) {
+                break;
+            }
+            long presentationTimeUs = videoExtractor.getSampleTime();
+            bufferInfo.offset = 0;
+            bufferInfo.size = sampleSize;
+            bufferInfo.flags = MediaCodec.BUFFER_FLAG_KEY_FRAME;
+            bufferInfo.presentationTimeUs = presentationTimeUs;
+            muxer.writeSampleData(videoTrack, buffer, bufferInfo);
+            videoExtractor.advance();
+        }
+    }
+
+    private void audioExtraction(ByteBuffer buffer, int audioTrack, MediaCodec.BufferInfo bufferInfo, MediaMuxer muxer) {
+        audioExtractor.seekTo(0, MediaExtractor.SEEK_TO_CLOSEST_SYNC);
+        while (true) {
+            int sampleSize = audioExtractor.readSampleData(buffer, 0);
+            if (sampleSize < 0) {
+                break;
+            }
+            long presentationTimeUs = audioExtractor.getSampleTime();
+            bufferInfo.offset = 0;
+            bufferInfo.size = sampleSize;
+            bufferInfo.flags = 0; // or MediaCodec.BUFFER_FLAG_KEY_FRAME
+            bufferInfo.presentationTimeUs = presentationTimeUs;
+            muxer.writeSampleData(audioTrack, buffer, bufferInfo);
+            audioExtractor.advance();
+        }
+    }
+
+    private void mergeVideoWithAudio() {
+        try {
+            newMediaExtractor(); //extrahieren der Video Datei, die zuvor zwischengespeichert wurde
+            newAudioExtractor(); //extrahieren der Audio Datei, die zuvor zwischengespeichert wurde
+
+            //Speicherort der später zusammengeführten Datei
+            String outputFilePath = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_MOVIES).getAbsolutePath() + "/merged_video.mp4";
+            //MediaMuxer zum Zusammenführen einer Audio- und einer Videodatei
+            MediaMuxer muxer = new MediaMuxer(outputFilePath, MediaMuxer.OutputFormat.MUXER_OUTPUT_MPEG_4);
+            int videoTrack = muxer.addTrack(videoFormat);
+            int audioTrack = muxer.addTrack(audioFormat);
+            muxer.start();
+
+            ByteBuffer buffer = ByteBuffer.allocate(1024 * 1024);
+            MediaCodec.BufferInfo bufferInfo = new MediaCodec.BufferInfo();
+
+            mediaExtraction(buffer, videoTrack, bufferInfo, muxer);
+            audioExtraction(buffer, audioTrack, bufferInfo, muxer);
+
+            muxer.stop();
+            muxer.release();
+
+            runOnUiThread(new Runnable() {
+                @Override
+                public void run() {
+                    Toast.makeText(MainActivity.this, "Video und Audio erfolgreich zusammengeführt", Toast.LENGTH_SHORT).show();
+                }
+            });
+
+            // Löschen der separaten Video- und Audio-Dateien
+            deleteVideoFile();
+            deleteAudioFile();
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+
+    private void deleteVideoFile(){
+        File videoFile = new File(videoPath);
+        if (videoFile.exists()) {
+            videoFile.delete();
+        }
+    }
+
+    private void deleteAudioFile(){
+        File audioFile = new File(audioPath);
+        if (audioFile.exists()) {
+            audioFile.delete();
+        }
+    }
+
+    private int getTrackIndex(MediaExtractor extractor, String mimeType) {
+        int trackCount = extractor.getTrackCount();
+        for (int i = 0; i < trackCount; i++) {
+            MediaFormat format = extractor.getTrackFormat(i);
+            String trackMimeType = format.getString(MediaFormat.KEY_MIME);
+            if (trackMimeType.startsWith(mimeType)) {
+                return i;
+            }
+        }
+        return -1;
     }
 }
\ No newline at end of file
diff --git a/app/src/main/res/layout/activity_main.xml b/app/src/main/res/layout/activity_main.xml
index 4fc2444..d24f56a 100644
--- a/app/src/main/res/layout/activity_main.xml
+++ b/app/src/main/res/layout/activity_main.xml
@@ -6,13 +6,26 @@
     android:layout_height="match_parent"
     tools:context=".MainActivity">
 
-    <TextView
+    <VideoView
+        android:id="@+id/videoView"
+        android:layout_width="1dp"
+        android:layout_height="1dp"
+        android:visibility="visible"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintHorizontal_bias="1.0"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent"
+        app:layout_constraintVertical_bias="0.0" />
+
+    <Button
+        android:id="@+id/button"
         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" />
+        android:layout_marginEnd="339dp"
+        android:text="Record Video"
+        app:layout_constraintHorizontal_bias="0.5"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent"/>
 
 </androidx.constraintlayout.widget.ConstraintLayout>
\ No newline at end of file