Whether you fly in competitions or are just plain fascinated and exacting with your aircraft tuning, a digital CG scale might be just the tool you are looking for.
It works like this.
With the plane setting in the yokes and the wings leading edge touching the vertical pins, the scale weighs the aircraft and calculates the CG similar to the way the CG is calculated for a full scale plane. The Arduino display shows both, the all up weight of the aircraft as well as the center of gravity in millimeters from the wings leading edge. The relatively high capacity of these scales allows you to CG your aircraft with the ballast on board. This makes ballast adjustments and CG tuning a snap.
Construction. At the heart of the scale are two highly sensitive, bending beam load cells. The load cells are connected to an Arduino CPU and the scales frame and yokes are 3d printed.
The cradles are 2.5" wide (between the pads) by 3" inches deep.
The scales are shipped calibrated and ready to use.