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Drone Drop System Hero Image
Electronics + Product Development
A wireless payload release system developed for mounting beneath a DJI Mavic 2 Pro, combining 433 MHz communication, custom electronics, PCB development, and 3D-printed hardware.
Type
Drone Payload System
Platform
DJI Mavic 2 Pro
Controllers
Arduino Nano + Pro Micro
Communication
433 MHz ASK
Development
Electronics + PCB
3D Printing
Project Context
Completed during high school as part of the Advanced Computer Engineering School program at Royal St. George's College. The project was developed to create a system capable of dropping payloads from the bottom of a Mavic 2 Pro drone.
References
01
The Drone Drop System uses separate transmitter and receiver electronics to wirelessly activate a payload release mechanism mounted beneath the drone.
The project was developed across five main areas: the 433 MHz modules, transmitter, receiver, custom PCB, and 3D-printed components.
The transmitter provides the user interface and sends the release command, while the receiver uses a micro servo to operate the release mechanism.
02
433 MHz transmitter and receiver modules form the wireless connection between the handheld controller and the payload release system.
The transmitter uses a SAW resonator tuned for 433 MHz operation. When a logic HIGH is applied to the DATA input, the oscillator produces a constant RF carrier wave. When the DATA input is LOW, the oscillator stops.
This communication method uses Amplitude Shift Keying. The receiver uses an RF tuned circuit and amplifiers before the signal is fed into a Phase Lock Loop to focus on the digital bit stream.
433 MHz Transmitter
Wireless transmitter module
433 MHz Receiver
Wireless receiver module
03
The transmitter combines an Arduino Nano, LCD, user controls, and a 433 MHz transmitter inside a dedicated 3D-printed case.
The Arduino Nano was selected for its size and available pins for driving the LCD and 433 MHz transmitter. The LCD acts as a status indicator for the user.
The transmitter is powered with 5V from the back of the DJI Smart Controller. RH.ASK controls the Amplitude Shift Keying communication and LiquidCrystal controls the status display.
Transmitter Assembly
Controller electronics and 3D-printed enclosure
Transmitter Components
Qty.
Arduino Nano
1
Liquid Crystal Display
1
10K Pot
1
Key Switch
1
Toggle Switch
1
DC Barrel Jack
1
Half Perma Proto
1
Male + Female Headers
Assorted
Wires
Assorted
04
The receiver uses an Arduino Pro Micro, 433 MHz receiver, and 5g micro servo to receive the wireless command and operate the release mechanism.
The Arduino Pro Micro was selected for its small size and power. It uses an onboard ATmega32U4, with all 18 Pro Micro IO pins available as digital inputs or outputs.
The receiver code uses RH.ASK for Amplitude Shift Keying communication and ServoTimer2 to control the release servo with PWM. ServoTimer2 was used to work around a conflict with Timer 1.
Receiver Assembly
Receiver electronics and release servo
Receiver Components
Qty.
Arduino Pro Micro
1
5g Micro Servo
1
433 MHz Receiver
1
Slide Switch
1
7.4V Cannon LP E-17 Battery
1
Custom PCB
1
Male Headers
Assorted
Custom Wire Harness
1
05
A custom PCB was developed to reduce the size of the receiver electronics and provide removable connections between components.
The PCB was designed in Autodesk Eagle. The circuit was first created as a schematic before being converted into the board layout.
Gerber files were exported and sent to JLC PCB. The board was designed to take up as little space as possible while fitting the required components. Male and female pin headers allow components to be connected and disconnected.
Receiver PCB
Custom receiver PCB
PCB Assembly
Soldered receiver electronics
06
The transmitter enclosure and drone-mounted receiver assembly were developed through multiple 3D-printed revisions.
Receiver
Four revisions were completed for the receiver side of the system. Weight, size, and clearance were the main design considerations.
Transmitter
Two revisions were completed for the transmitter side of the system.
Fabrication
All 3D-printed components for the project were produced on an Ender 3 Pro.
Receiver + Transmitter Enclosure Development
Iterative 3D-printed hardware
Ender 3 Pro
07
The completed system combines a dedicated transmitter with a compact drone-mounted receiver to wirelessly control the payload release servo.
The transmitter uses an Arduino Nano, LCD, and 433 MHz transmitter module to provide the user interface and send the release command.
On the drone, the Arduino Pro Micro and 433 MHz receiver receive the command and control the 5g micro servo through the custom receiver electronics.
Final Drone Drop System
Wireless payload release system
DJI Mavic 2 Pro