ChaddRainsFPV O4 ArmerIntroducing the ChaddRainsFPV O4 Armer (Compatible with O3) If you've ever wanted to add O4 O3 HD FPV to an RC car, boat, plane or anything else without a flight controller, the O4 Armer is exactly what you need! The DJI O4 O3 video system will not output its full power unless there is an 'armed' signal sent to it, like you'd get from a flight controller. The O4 Armer sends this 'armed' signal after being powered on for ~20 seconds, automatically.