Drone Payload Drop with a Servo Release
A 3D-printed hook opened by a servo from a switch on your radio — for fishing lines, markers or rescue tests.
ArduPilot can drive a spare servo output from a radio channel or a mission command. A tiny release hook turns your drone into a delivery test platform.
Dropping objects from drones is restricted in many places. In the U.S., recreational pilots must pass the free FAA TRUST test, register drones over 250 g (0.55 lb), comply with Remote ID and keep the aircraft within visual line of sight (FPV pilots need a visual observer). Rules change — check faa.gov before you fly.
Mission steps
Print the release
Design or print a hook with a pin that a servo arm pulls out. Keep it light — every gram cuts flight time.
Wire the servo
Connect the servo to a free flight-controller output and power it from the FC's 5 V servo rail or a small BEC.
Map it in ArduPilot
Set that output's SERVOx_FUNCTION to RCIN passthrough for the channel of a spare switch, or use the Gripper feature.
Test on the bench
Props off. Flip the switch and confirm the hook opens and closes fully.
Drop over a safe area
Release only small, soft test weights over an empty field.
Questions
How much can a 5-inch quad carry?
A few hundred grams at most, with much shorter flights. Use the Drone Thrust calculator with the payload added to the weight.