Disable LDW for 4 seconds after blinker transition from on to off (#112)

If we want to change lanes with a blinker tap (3 blink mode), then we need to disable LDW for enough time to allow a smooth manual lane change. 4 seconds as it seems the freq is actually around 50Hz, not 100Hz.

selfdrive/car/tesla/carcontroller.py

@@ -196,7 +196,12 @@ def __init__(self, dbc_name):
     self.prev_ldwStatus = 0
 
     self.radarVin_idx = 0
-
+
+    self.LDW_NUMB_PERIOD = 200 # 4 seconds at 50Hz 
+    self.should_ldw = False
+    self.ldw_numb_frame_start = 0
+    self.prev_changing_lanes = False
+
     self.isMetric = (self.params.get("IsMetric") == "1")
 
   def reset_traffic_events(self):
@@ -317,6 +322,17 @@ def update(self, enabled, CS, frame, actuators, \
 
     # Basic highway lane change logic
     changing_lanes = CS.right_blinker_on or CS.left_blinker_on
+
+    if (frame % 25 == 0):
+      if (self.prev_changing_lanes and not changing_lanes): #we have a transition from blinkers on to blinkers off, save the frame
+        self.ldw_numb_frame_start = frame
+        print("LDW Transition detected, frame (%d)", frame)
+
+      # update the previous state of the blinkers (chaning_lanes)
+      self.prev_changing_lanes = changing_lanes
+
+      #Determine if we should have LDW or not
+      self.should_ldw = (frame > (self.ldw_numb_frame_start + self.LDW_NUMB_PERIOD))
 
     #upodate custom UI buttons and alerts
     CS.UE.update_custom_ui()
@@ -738,7 +754,8 @@ def handlePathPlanSocketForCurvatureOnIC(self, pathPlanSocket, alcaStateData, CS
           self.curv0 = self.ALCA.laneChange_direction * self.laneWidth - self.curv0
         self.curv0 = clip(self.curv0, -3.5, 3.5)
       else:
-        if CS.enableLdw and (not CS.blinker_on) and (CS.v_ego > 15.6) and (turn_signal_needed == 0):
+        if self.should_ldw and (CS.enableLdw and (not CS.blinker_on) and (CS.v_ego > 15.6) and (turn_signal_needed == 0)):
+          self.ldw_numb_frame_start = 0 #reset frame_start for the transition
           if pp.lProb > LDW_LANE_PROBAB:
             lLaneC0 = -pp.lPoly[3]
             if abs(lLaneC0) < LDW_WARNING_2: