The goal of this project was to develop a self-contained, Arduino-based device to display relevant information about a remote-controlled aircraft's weight, center of gravity (CG), and stability to the flight crew prior to takeoff.
The system utilizes 3 strain gauge scales to measure the weight under each wheel of the aircraft. Then, the weights are processed to calculate the total weight and CG location. Finally, this data is combined with pre-programmed aircraft geometry to project the CG onto the wing's mean aerodynamic chord (MAC).
The electronics enclosure was designed to house the Arduino and LCD display in a manner that kept it safe, made visible the enclosed wiring, kept each component accessible for future modifications, and allowed for easy access to the Arduino's USB port. Additional functionality from 4 buttons and 2 LEDs can be added later through software modifications.
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(1) Initial circuitry of the LCD display, buttons, and LEDs on the Lexan cover. (2) Final system circuitry prior to soldering on the strain gauges.
A CNC router was used to cut the electronics enclosure and a cup-shaped piece for the aircraft wheels to sit in while on the scales (shown at the end).
Final circuitry with the Arduino mounted to the enclosure and the strain gauges soldered in place.
Final enclosure: (1) left side where the strain gauge wires enter, (2) right side where the battery (2S or 3S LiPo) and USB ports are located.
Full system: (1) stored, (2) laid out - envision an aircraft set in place with its nosewheel on the top left scale and its main gear on the bottom right scales.
Using the CG Display on the Embry-Riddle Aeronautical University Daytona Beach aircraft for the 2022 AIAA Design, Build, Fly competition. Watch the video here.
LCD display showing total weight and CG location.