Which model drone and Gannet do you have? I have a M2 Pro and bought the M2 specific Gannet that activates from the M2 aux light under the main body. Only problem is it doesn't work. The Gannet light sensor simply ignores the M2 LED and the release pin remains open when it should shut. I also tested the Gannet using my iPhone flashlight LED and it works just fine. So there is something different between the two LEDs... intensity, color temp, etc. that makes the Gannet "blind" to the M2 LED. The company is pretty poor in responding. They claim to be having e-mail inbox issues and losing or misplacing e-mails. So far all I have gotten from them is to "try to calibrate the sensor". I mean that cursory a reply that doesn't offer a clue as to how to do that... and the unit itself has no calibrate or reset button, only an on-off switch... and their website doesn't have a manual or technical support link. Maybe it is something like flip the on-off switch 3 times to put it in cal mode then shine the light on the sensor for 5 seconds... or, who knows??
Yes, these can be used for many applications. Maybe teach the wifey to fly and have her send me cold beers out in the yard? But I plan to take it to Florida for some fishing.