Follow Line Indicator draws one line under or over price that can only move one way, on
MT4 and MT5. It's a trailing stop that a Bollinger break turns on, and it will sit
perfectly flat for fifty bars rather than drift back toward price.

Follow Line on XAUUSD H1, a teal line ratcheting up under price then flipping to orange

Two parts, and the second one is the interesting half

The Bollinger break decides direction. A 21 period SMA with bands at 1.0 standard
deviation, on the close. Close above the upper band and it's an uptrend, close below the
lower band and it's a downtrend. Close anywhere in between and nothing changes, which is
most bars.

That 1.0 deviation matters. Default Bollingers use 2.0, where a close outside the band is
a rare event. At 1.0 the bands sit close enough that a decent push through them counts,
so the tool reacts to a move starting rather than to a move that has already gone.

The ratchet draws the line. In an uptrend the line goes to low − ATR(5). On the next
bar it recalculates, and if the new value is lower than the old one, it keeps the old
one. In a downtrend it's high + ATR(5), and it can only go down.

So the line follows price up and never follows it back. When the Bollinger says nothing,
the line holds its last value exactly. That's the flat stretch you see on the chart before
each flip.

The flip is the signal

When the ratchet direction reverses, the line changes colour and an arrow prints at the
line's level: teal going up, chocolate going down, blue arrow up, red arrow down.

A flip isn't a soft crossover. In an uptrend the line only turns over if high + ATR on
the current bar lands below the line the ratchet had already dragged up. Price has to
give back the whole trail, in one bar, to earn a flip. That's why they're comparatively
rare and why the flat stretches survive so long.

The same tool on EURUSD M15, two down flips and one up flip across a session

The ATR filter is a distance switch, not a filter

ATR Filter is on by default and the name undersells it. On, the line sits one ATR(5)
away from the bar's low or high. Off, it sits on the low or high itself.

Turned off you get a line that hugs price, flips far more often, and gets clipped by
ordinary noise. Turned on you get room. ATR Period at 5 is short on purpose, so the
distance tracks the last handful of bars rather than the last month.

If you want it tighter without turning the filter off, raise ATR Period on a quiet
symbol and lower it on a volatile one. Raising the period smooths the distance; it doesn't
shrink it.

MT4 and MT5

Same Bollinger, same ratchet, same flips. Below is the MT4 build on gold, showing the same
behaviour: a long flat hold, then a flip with the arrow at the line rather than at price.

The MT4 build on XAUUSDm H1 with a teal hold and a flip to orange

Two differences worth knowing:

  • MT4 has an Alert? switch and colour inputs for the two arrows. MT5 handles both
    through Signal Notification, which includes a "do not notificate" option.
  • The internal buffers are in a different order. On MT5, buffer 0 is the up line and 1 is
    the down line; on MT4 they're swapped. If you're reading this with iCustom from an EA,
    check which platform you're on.

Reading it from an EA

Buffer 5 holds the trend state as a plain +1 or −1 on both platforms, and it's already
the ratcheted, filtered answer. Buffer 4 holds the line value itself. Those two are the
useful ones for anything automated. The four plotted buffers are for the chart: they carry
EMPTY_VALUE on every bar where their side of the trend isn't active.

Repainting, honestly

Closed bars don't move. Past line values and past arrows stay where they are, and the
calculation only revisits the newest bar after the first pass.

The newest bar does move, and this is the part to be honest about. While a bar is
forming, its low and high change, so the line value changes with them, and a flip can
appear and then be taken back before the bar closes. The alert fires on that forming bar,
guarded by a one alert per bar timestamp, so you can get a buy alert at 14:03 and have the
arrow gone by 15:00.

That is a real weakness, not a footnote. If you're acting on the alerts, treat one as
"check the chart", not as "the bar closed like this". Wait for the close and the arrow is
final.

What it doesn't do

  • No multi-timeframe. One chart, one line.
  • No entries, stops or targets. The line is a trailing level. What you do at a flip is
    your call.
  • No email alerts. Popup and mobile push only.
  • No labels or on-chart text. Nothing but the two lines and the two arrows.
  • Lookback is 500 bars on the first pass. Scroll back further than that and the
    earliest bars are blank until it recalculates.

Settings I'd start with

Leave BB Period at 21 and BB Deviations at 1.00. Raising the deviation toward 2.0 turns
this into a very slow tool that changes direction two or three times a year on a daily
chart. Some people want that. Most don't, and the ratchet already supplies the patience.

Keep ATR Filter on. That's the setting that separates this from a low-of-the-bar trailing
stop, which every platform already ships.

Signal Notification defaults to popup only. If you're at the screen anyway, set it to
"do not notificate" and read the colours instead, given what I said above about the
forming bar.

H1 and H4 suit it better than M5. On M5 the Bollinger break at 1.0 deviation fires
constantly, and the ratchet spends its time being reset.

Questions you'll have

Does Follow Line Indicator repaint? History doesn't. The newest bar does, until it
closes: the line moves with the forming bar's high and low, and a flip on that bar can be
withdrawn. Everything behind it is fixed.

Why is the line flat for so long? Because price is inside the Bollinger bands. No
break, no update, so it holds its last value. That's the design, not a freeze.

Can I use it as a stop loss? People do, and the ratchet makes it a reasonable trailing
level. Just know it's built from the low minus an ATR, so it sits where an ordinary
pullback can reach it on a fast symbol.

Why did the arrow disappear? You saw it on a forming bar. Wait for the close.

MT4 too? Both builds are included, one download each.

What does turning off the ATR filter do? Puts the line right on the bar's low or high
instead of an ATR away. It flips far more often. I'd leave it on.

Which timeframe? H1 and above. It works on lower ones, but the flip count climbs fast.

Both platform builds come with a subscription. No profitability claim here: this marks a
trend direction and a trailing level, and neither of those tells you where to get out with
a profit. If an indicator listing shows you a win rate, ask what settings and what symbol
produced it.