I made it using a Light dependant resistor looking at one of the front leds, a FET & a small 10 turn pot. The leds are 12v & in a stick, which is attached to the carbon fibre camera saver [ which also stiffens up the legs enormously]. I have tapped power off the back of the main battery connector inside the drone. There are 4 diodes in series with the led stick to drop the voltage to about 12v. It's a bit rough & ready, but it works perfectly. I don't notice any drop in airtime with the lights on. The pot is on top of the fet, which does not need a heatsink. I can draw you a diagram if that helps. The wires come straight down, rather than being tied to a leg, which is likely to upset the radio aerial & the compass.
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