It has to be minimum of 2-3 consecutive bars on the same direction of the trend.
But not less important is the minimum range, and this one has to be a parameter that the user can change its value, since it has to be X pips in 15 minutes chart and higher in 4 hours chart.
But not less important is the minimum range, and this one has to be a parameter that the user can change its value, since it has to be X pips in 15 minutes chart and higher in 4 hours chart.