Every developer must create his own Relative Strength Index with midline and other features).
In addition to the midline, highlighting and levels customization I give you ability to play with non-standard sources like On Balance Volume.
If someone doesn't know what is this:
This indicator was originally developed by J. Welles Wilder and was described in his book "New Concepts in Technical Trading Systems" (1978). It is intended to measure the strength or weakness of an instrument for the specified period.
RSI is a momentum oscillator and can have a reading from 0 to 100. The values of 70 or above indicate that an instrument is becoming overbought or overvalued and may be primed for a trend reversal or corrective pullback in price. The values of 30 or below indicates an oversold or undervalued condition.
The other significant signals are divergences with price and middle line crossovers. RSI if one the most used indicators on the planet.
Enjoy and good luck!