Atlantean Sideways / Range Regime Detector

Purpose
When using trend based indicators, you can skip the false signals when there is a sideways action, protecting you from the false signals.
Flags likely sideways/range phases using three checks:

• Weak trend (ADX from DMI)
  
• Price compression (Bollinger Band Width, normalized)
  
• Low volatility (NATR = ATR/Price%)
  

Logic

• isSideways = (ADX < adxThresh) AND (bbNorm < 0.25) AND (NATR < natrMax)

• When true: bars + background turn teal and a provisional Range High/Low (rolling rangeWin) is drawn.
  

Key Inputs

• DMI: diLen(22)
  Optimized for 15 mins Bitcoin, could change it to 14 for more general approach
• ADX: adxSmooth(14), adxThresh(18)
  
• Volatility: lenATR(14), natrMax(1.8)
  
• Visuals: rangeWin(20), bar/range toggles
  

Quick Tuning

• More signals: raise adxThresh to 20–25, raise natrMax to 2.5–4.0, increase BB cutoff by editing bbNorm < 0.25 --> 0.35–0.50.
  
• Smoother range lines: increase rangeWin to 30–40.
  

Use Cases

• Mean reversion inside teal ranges.
  
• Breakout prep when price closes outside the drawn range after teal ends. Could be used as a signal although not suggested.
  
• Filter trend systems: skip trades when sidewaysCond is true. This is the main purpose, for it to be combined with trend based indicators, like Supertrend.

Alert

• “Sideways Detected” triggers when isSideways is true.
  

Script could be expanded upon your requests.