Copter: move lost copter check to separate function

Also run from scheduler instead of from arm/disarm stick checks
Run at 10hz instead of 1hz
soundalarm_counter to uint8
Disable if equivalent aux switch is setup
Remove SEVERITY_LOW message because the GCSs never print these anyway

ArduCopter/ArduCopter.pde

@@ -742,6 +742,7 @@ static const AP_Scheduler::Task scheduler_tasks[] PROGMEM = {
     { ekf_check,            40,      2 },
     { crash_check,          40,      2 },
     { landinggear_update,   40,      1 },
+    { lost_vehicle_check,   40,      2 },
     { gcs_check_input,       1,    550 },
     { gcs_send_heartbeat,  400,    150 },
     { gcs_send_deferred,     8,    720 },

ArduCopter/motors.pde

@@ -4,7 +4,7 @@
 #define DISARM_DELAY            20  // called at 10hz so 2 seconds
 #define AUTO_TRIM_DELAY         100 // called at 10hz so 10 seconds
 #define AUTO_DISARMING_DELAY    15  // called at 1hz so 15 seconds
-#define NOTIFY_LOCATION_DELAY   1   // called at 1hz so 1 seconds
+#define LOST_VEHICLE_DELAY      10  // called at 10hz so 1 second
 
 static uint8_t auto_disarming_counter;
 
@@ -72,26 +72,6 @@ static void arm_motors_check()
 // called at 1hz
 static void auto_disarm_check()
 {
-    static int16_t soundalarm_counter;
-
-    // ensure throttle is down, motors not armed, pitch and roll rc at max. Note: rc1=roll rc2=pitch
-    if (!g.rc_3.control_in > 0 && !motors.armed() && g.rc_1.control_in > 4000 && g.rc_2.control_in > 4000) {
-        if (soundalarm_counter >= NOTIFY_LOCATION_DELAY) {
-            if (AP_Notify::flags.vehicle_lost == false) {
-                AP_Notify::flags.vehicle_lost = true;
-                gcs_send_text_P(SEVERITY_HIGH,PSTR("Locate Copter Alarm!!"));
-            }
-        } else {
-            soundalarm_counter++;
-        }
-    }else{
-        soundalarm_counter = 0;
-        if (AP_Notify::flags.vehicle_lost == true) {
-            AP_Notify::flags.vehicle_lost = false;
-            gcs_send_text_P(SEVERITY_LOW,PSTR("Locate Copter Alarm Off"));
-        }
-    }
-
     // exit immediately if we are already disarmed or throttle is not zero
     if (!motors.armed() || !ap.throttle_zero) {
         auto_disarming_counter = 0;
@@ -749,3 +729,31 @@ static void motors_output()
         motors.output();
     }
 }
+
+// check for pilot stick input to trigger lost vehicle alarm
+static void lost_vehicle_check()
+{
+    static uint8_t soundalarm_counter;
+
+    // disable if aux switch is setup to vehicle alarm as the two could interfere
+    if (check_if_auxsw_mode_used(AUXSW_LOST_COPTER_SOUND)) {
+        return;
+    }
+
+    // ensure throttle is down, motors not armed, pitch and roll rc at max. Note: rc1=roll rc2=pitch
+    if (ap.throttle_zero && !motors.armed() && (g.rc_1.control_in > 4000) && (g.rc_2.control_in > 4000)) {
+        if (soundalarm_counter >= LOST_VEHICLE_DELAY) {
+            if (AP_Notify::flags.vehicle_lost == false) {
+                AP_Notify::flags.vehicle_lost = true;
+                gcs_send_text_P(SEVERITY_HIGH,PSTR("Locate Copter Alarm!"));
+            }
+        } else {
+            soundalarm_counter++;
+        }
+    } else {
+        soundalarm_counter = 0;
+        if (AP_Notify::flags.vehicle_lost == true) {
+            AP_Notify::flags.vehicle_lost = false;
+        }
+    }
+}