The Instantaneous Trendline was created by John Ehlers (Rocket Science For Traders pgs 109-110) and this indicator is perfect for determining the medium to long term trend. Buy when the indicator line is green and sell when it is red. I will be introducing a different version of this indicator which is perfect for short term trends so these will pair great together.
Let me know if there are other scripts you would like to see me publish or if you want something custom done!