diff --git a/msg/vehicle_command.msg b/msg/vehicle_command.msg
index 391dc01aa0..2f223fbc2e 100644
--- a/msg/vehicle_command.msg
+++ b/msg/vehicle_command.msg
@@ -48,7 +48,8 @@ uint32 VEHICLE_CMD_PREFLIGHT_REBOOT_SHUTDOWN = 246	# Request the reboot or shutd
 uint32 VEHICLE_CMD_OVERRIDE_GOTO = 252			# Hold / continue the current action |MAV_GOTO_DO_HOLD: hold MAV_GOTO_DO_CONTINUE: continue with next item in mission plan| MAV_GOTO_HOLD_AT_CURRENT_POSITION: Hold at current position MAV_GOTO_HOLD_AT_SPECIFIED_POSITION: hold at specified position| MAV_FRAME coordinate frame of hold point| Desired yaw angle in degrees| Latitude / X position| Longitude / Y position| Altitude / Z position| 
 uint32 VEHICLE_CMD_MISSION_START = 300			# start running a mission |first_item: the first mission item to run| last_item:  the last mission item to run (after this item is run, the mission ends)| 
 uint32 VEHICLE_CMD_COMPONENT_ARM_DISARM = 400		# Arms / Disarms a component |1 to arm, 0 to disarm| 
-uint32 VEHICLE_CMD_START_RX_PAIR = 500			# Starts receiver pairing |0:Spektrum| 0:Spektrum DSM2, 1:Spektrum DSMX| 
+uint32 VEHICLE_CMD_START_RX_PAIR = 500			# Starts receiver pairing |0:Spektrum| 0:Spektrum DSM2, 1:Spektrum DSMX|
+uint32 VEHICLE_CMD_DO_TRIGGER_CONTROL = 2003            # Enable or disable on-board camera triggering system
 uint32 VEHICLE_CMD_PAYLOAD_PREPARE_DEPLOY = 30001	# Prepare a payload deployment in the flight plan
 uint32 VEHICLE_CMD_PAYLOAD_CONTROL_DEPLOY = 30002	# Control a pre-programmed payload deployment
 
diff --git a/src/modules/camera_trigger/camera_trigger.cpp b/src/modules/camera_trigger/camera_trigger.cpp
index 883048ba0c..c0a43f9255 100644
--- a/src/modules/camera_trigger/camera_trigger.cpp
+++ b/src/modules/camera_trigger/camera_trigger.cpp
@@ -151,7 +151,7 @@ CameraTrigger::CameraTrigger() :
 	_trigger_enabled(true),
 	_sensor_sub(-1),
 	_vcommand_sub(-1),
-	_trigger_pub(-1),
+	_trigger_pub(nullptr),
 	_trigger{}
 {
 	memset(&_trigger, 0, sizeof(_trigger));