Designing the frame in AutoCAD:
- Create the basic drone shape using line and circle (make sure the unit is in mm). Also add the symmetrical line for placing the components in perfectly balanced way so it will reduce the complexity in drone algorithm and make it stable. Add curved edge for making it more durable. Decide the drone size based the propeller, there are wide size available(40mm,55mm,65mm),55 mm will be the best suit for 8520 motors.
- Once the design is finished, add the outer square of 10x10 cm and then save the diagram as .dxf format.
Circuit design in EASYEDA:
- Now start designing the circuit in EASYEDA.
- Create new project and draw the schematic.
- Use the net port to make the schematic look clean and neat.
- Once the schematic is over click on design -> convert schematic to PCB.
- Allow the DRC check to verify the schematic.
- Make sure there is no errors and warnings.
Importing dxf file to EASYEDA:
- Once the PCB is created, now we can import the diagram from AutoCAD.
- Choose the drawing file(.dxf format)
- Make sure to choose layer type as BoardOutLine and Stroke Width as 0.245 mm
- Enable the Convert circle to HOLE on BoardOutLine layer check box, which will make hole for the motor mount.
- Start arrange the components as symmetrical as possible.
- Keep mosfet near the motor, which cool down the mosfet from extreme during flying by the airflow from propeller.
- Keep the IMU as center as possible, which will make the drone stable and reduce the complexity in algorithm.
- Add the Silk screen Arrow mark denoting the front of the drone, which will be helpful during flying.
- Add circular arrow mark which is denoting the rotation of the motor, which will be helpful during fixing of motor.
- Remove the symmetrical line.
- Now use the AutoRouter or manual Route all the track.
- Most recommend will be Manual Route.
- Increase the width of Power line.
- Each motor can consume up to 2A, In case of track with 0.25 mm the track will get burn, So the recommended width is (0.4 to 1mm) for motor power line.
- Use 2D or 3D view features to view the final PCB.
- Add all the terminal markings is the Silk screen, which prevent the accidental reverse polarity connection.
- Once satisfied with final view export the gerber file (File->Generate PCB Fabrication File(Gerber)…
- Give YES to DRC check, which will ensure there is no error is PCB design.
- Now upload the gerber file to PCBWay and choose thickness as 1.2mm.
- I have tested the thickness of PCB like 1mm,1.2mm,1.6mm.
- 1.6mm is the more standard one but it will add some weight to the drone, 1mm and less than 1mm add more flexibility to drone which make it useless and 1.2mm is best choice which give less flexibility as well as less weight and good strength for the frame.
- During field test the drone had lot of crash, the 1.2mm PCB survived well just got few scratches around the arm of the drone.
- I hope this gives an Idea about how to create a custom shape for PCB design.