diff --git a/.gitignore b/.gitignore
new file mode 100644
index 00000000..962b63d4
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,9 @@
+################################################################################
+# This .gitignore file was automatically created by Microsoft(R) Visual Studio.
+################################################################################
+
+/.vs
+/obj/Debug/BerlinClock.csprojAssemblyReference.cache
+/bin/Debug
+/obj/Debug
+/packages
diff --git a/Classes/TimeConverter.cs b/Classes/TimeConverter.cs
index dd5bf4e0..3fdc5726 100644
--- a/Classes/TimeConverter.cs
+++ b/Classes/TimeConverter.cs
@@ -1,6 +1,4 @@
 using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 
 namespace BerlinClock
@@ -9,7 +7,137 @@ public class TimeConverter : ITimeConverter
     {
         public string convertTime(string aTime)
         {
-            throw new NotImplementedException();
+            TimeSpan time = ParseTimeString(aTime);
+            string clockLampsString = BuildBerlinClockString(time);
+            return clockLampsString;
+        }
+
+        private TimeSpan ParseTimeString(string timeString)
+        {
+            var invariantCultureInfo = System.Globalization.CultureInfo.InvariantCulture;
+
+            if (string.IsNullOrWhiteSpace(timeString))
+            {
+                throw new ArgumentException("Time string parameter is null or empty", "timeString");
+            }
+
+            string[] timeParts = timeString.Split(new char[] { ':' }, StringSplitOptions.RemoveEmptyEntries);
+            if (timeParts.Length != 3)
+            {
+                throw new ArgumentException("Time string format is not valid", "timeString");
+            }
+
+            int hours, minutes, seconds;
+            if (!int.TryParse(timeParts[0], System.Globalization.NumberStyles.Integer, invariantCultureInfo.NumberFormat, out hours)
+                || !int.TryParse(timeParts[1], System.Globalization.NumberStyles.Integer, invariantCultureInfo.NumberFormat, out minutes)
+                || !int.TryParse(timeParts[2], System.Globalization.NumberStyles.Integer, invariantCultureInfo.NumberFormat, out seconds)
+            )
+            {
+                throw new ArgumentException("Time string format is not valid", "timeString");
+            }
+
+            if (hours < 0 || hours > 24)
+            {
+                throw new ArgumentOutOfRangeException("Hours");
+            }
+            if (minutes < 0 || hours > 59)
+            {
+                throw new ArgumentOutOfRangeException("Minutes");
+            }
+            if (seconds < 0 || seconds > 59)
+            {
+                throw new ArgumentOutOfRangeException("Seconds");
+            }
+
+            return new TimeSpan(hours, minutes, seconds);
+        }
+
+        private string BuildBerlinClockString(TimeSpan time)
+        {
+            int hours = (int)time.TotalHours;
+            int minutes = time.Minutes;
+            int seconds = time.Seconds;
+
+            StringBuilder result = new StringBuilder();
+            result.AppendFormat("{0}\r\n", TwoSecondsLamp(seconds));
+            result.AppendFormat("{0}\r\n", FiveHoursLamps(hours));
+            result.AppendFormat("{0}\r\n", OneHourLamps(hours));
+            result.AppendFormat("{0}\r\n", FiveMinutesLamps(minutes));
+            result.AppendFormat("{0}", OneMinuteLamps(minutes));
+            return result.ToString();
+        }
+
+        private string TwoSecondsLamp(int seconds)
+        {
+            return seconds % 2 == 0 ? "Y" : "O";
+        }
+
+        private string FiveHoursLamps(int hours)
+        {
+            StringBuilder result = new StringBuilder();
+
+            int lampsOn = hours / 5;
+            int lampsOff = 4 - lampsOn;
+            for (int l = 0; l < lampsOn; l++)
+            {
+                result.Append("R");
+            }
+            for (int l = 0; l < lampsOff; l++)
+            {
+                result.Append("O");
+            }
+            return result.ToString();
+        }
+
+        private string OneHourLamps(int hours)
+        {
+            StringBuilder result = new StringBuilder();
+
+            int lampsOn = hours % 5;
+            int lampsOff = 4 - lampsOn;
+            for (int l = 0; l < lampsOn; l++)
+            {
+                result.Append("R");
+            }
+            for (int l = 0; l < lampsOff; l++)
+            {
+                result.Append("O");
+            }
+            return result.ToString();
+        }
+
+        private string FiveMinutesLamps(int minutes)
+        {
+            StringBuilder result = new StringBuilder();
+
+            int lampsOn = minutes / 5;
+            int lampsOff = 11 - lampsOn;
+            for (int l = 1; l <= lampsOn; l++)
+            {
+                result.Append(l % 3 == 0 ? "R" : "Y");
+            }
+            for (int l = 1; l <= lampsOff; l++)
+            {
+                result.Append("O");
+            }
+            return result.ToString();
+        }
+
+        private string OneMinuteLamps(int minutes)
+        {
+            StringBuilder result = new StringBuilder();
+
+            int lampsOn = minutes % 5;
+            int lampsOff = 4 - lampsOn;
+            for (int l = 1; l <= lampsOn; l++)
+            {
+                result.Append("Y");
+            }
+            for (int l = 1; l <= lampsOff; l++)
+            {
+                result.Append("O");
+            }
+            return result.ToString();
         }
     }
 }