I had hoped to produce an amateur documentary about local nature with my kids. The primary setting was to be the small creek nearby. The weather was perfect for being outdoors and for flying. Unfortunately, due to pilot error (failure to consider the behavior of the drone immediately after take-off), the video shoot turned into a lesson in small unmanned aerial vehicle recovery instead!
Most of the time, I find flying the DJI Spark to be enjoyable and predictable. That is, the onboard computer does a good job keeping the drone from drifting and erratic flight. This makes me happy. However, occasionally during flight and especially right after power-on the onboard computer and sensors can act erratically. On this fateful flight to the bottom of a creek, I surmise that the compass, GPS, and accelerometers had not engaged before the drone drifted into a tree. The drone went from airborne to submerged in 2 feet of water in less than 45 seconds!
I didn’t have much time to react. I jumped into the creek and pulled the drone from the bottom of the creek. Amazingly, the drone was still running when I pulled it out of the water. Specifically, I could hear the cooling fan and the lights were still blinking. I quickly powered off the drone to avoid shorting out any circuits!
When I got back to my work bench, I dried out the DJI Spark by:
- Removing the bottom 6 hex screws
- Carefully removing the plastic top cover
- Placing the drone in a large ziplock bag
- Filling small perforated bags with silica beads (from Hobby Lobby)
- Placing the bags of silica in the larger ziplock bag
- Leaving the drone to dry in the bag for 5 days
I’ve heard elsewhere that one should not use a lithium battery that has been wet. I haven’t researched why this is, but I do know that my submerged battery would not retain a charge either by design or due to damage.
Here’s a quick video showing how I dried out the DJI Spark.