I have an old drone with a RF camera. When powered (12v drone battery) it turns on and transmits the video to a paired First Person View monitor, it also starts recording onto an SD card (on the drone), works fine. My problem is that when I disconnect the power, the SD card does not save the recorded file. I have to push a momentary button on the pcb to stop the recording, allowing it time to save before I can remove the power.
I want an Arduino to "push" that button form me. I could use a relay, but it's big and bulky, unless anyone knows of something really small?? I thought about an optocoupler (but previous failed attempts on other devices have put me off trying to understand those things, am i using it wrong?), and just using a 2n2222 transistor and connect the grounds, but I don't want to fry the circuit "experimenting". I figure you guys would need to know something about the circuit the where the button is pushed but all I have is this:
There is a picture of the main PCB i'm talking about, the 3 cables go the camera, the 5 cables go to another part of the RF transmitter PCB and where the 12v supplies. It says 5V is powering the PCB with the button (Start/Stop Record). The SD card is on the underside of this PCB.
What do I do??