diff --git a/Server/Client.cs b/Server/Client.cs
index 5e385be..fc4baca 100644
--- a/Server/Client.cs
+++ b/Server/Client.cs
@@ -123,15 +123,23 @@ namespace Server
                         Console.WriteLine($"Received json with identifier {identifier}:\n{Encoding.ASCII.GetString(payloadbytes)}");
                         break;
                 }
-                Array.Copy(message, 5, payloadbytes, 0, message.Length - 5);
-                dynamic json = JsonConvert.DeserializeObject(Encoding.ASCII.GetString(payloadbytes));
-                saveData.WriteDataJSON(Encoding.ASCII.GetString(payloadbytes));
-
+                saveData?.WriteDataJSON(Encoding.ASCII.GetString(payloadbytes));
             }
             else if (DataParser.isRawData(message))
             {
-                Console.WriteLine(BitConverter.ToString(message));
-                saveData.WriteDataRAW(ByteArrayToString(message));
+                Console.WriteLine(BitConverter.ToString(payloadbytes));
+                if (payloadbytes.Length == 8)
+                {
+                    saveData.WriteDataRAWBike(payloadbytes);
+                }
+                else if (payloadbytes.Length == 2)
+                {
+                    saveData.WriteDataRAWBPM(payloadbytes);
+                }
+                else
+                {
+                    Console.WriteLine("received raw data with weird lenght " + BitConverter.ToString(payloadbytes));
+                }
             }
 
 
diff --git a/Server/SaveData.cs b/Server/SaveData.cs
index 0286bde..4163471 100644
--- a/Server/SaveData.cs
+++ b/Server/SaveData.cs
@@ -22,21 +22,53 @@ namespace Server
         /// <summary>
         ///  Every line is a new data entry
         /// </summary>
-       
+
         public void WriteDataJSON(string data)
         {
-            using (StreamWriter sw = File.AppendText(this.path + "/json"+filename+".txt"))
+            using (StreamWriter sw = File.AppendText(this.path + "/json" + filename + ".txt"))
             {
                 sw.WriteLine(data);
             }
         }
 
-        public void WriteDataRAW(string data)
+        public void WriteDataRAWBPM(byte[] data)
         {
-            using (StreamWriter sw = File.AppendText(this.path + "/raw" + filename + ".txt"))
+            if (data.Length != 2)
             {
-                sw.WriteLine(data);
+                throw new ArgumentException("data should have length of 2");
+            }
+            WriteRawData(data, this.path + "/rawBPM" + filename + ".bin");
+        }
+
+        public void WriteDataRAWBike(byte[] data)
+        {
+            if (data.Length != 8)
+            {
+                throw new ArgumentException("data should have length of 8");
+            }
+            WriteRawData(data, this.path + "/rawBike" + filename + ".bin");
+        }
+
+        private void WriteRawData(byte[] data, string fileLocation)
+        {
+            int length = 0;
+            try
+            {
+                FileInfo fi = new FileInfo(fileLocation);
+                length = (int)fi.Length;
+            }
+            catch
+            {
+                // do nothing
+            }
+            using (BinaryWriter sw = new BinaryWriter(File.Open(fileLocation, FileMode.Create)))
+            {
+                sw.Seek(length, SeekOrigin.End);
+                sw.Write(data);
+                sw.Flush();
             }
         }
+
+
     }
 }