Introduction: Designing an Electronic Mount in CAD

Whether or not you plan to specialize in mechanical engineering, Computer-Aided Design (CAD) is a powerful tool that plays a key role in integrating electrical systems into rockets and payloads. These mounts secure hardware, organize wiring, and ensure accessibility for testing and integration.

In this workshop, we will design a mount for a Featherweight GPS Tracker and its LiPo battery using Onshape. While the example is simple, it will introduce you to the broader design considerations we as engineers face when integrating electronics into constrained and dynamic environments like rockets.

There are several factors involved when designing a mount, each of varying priority depending on the situation. Sometime sizing is a huge constraint like in the payload:

Factors that Influence Design Choices:

Beyond simply holding parts in place, designing an electronic mount involved balancing several factors, such as:

1. Space Constraints

   • Rockets and CubeSat payloads often have strict dimensional limits. For example, here is a CAD of one of our final prototypes of the electrical mount for last year’s payload. It was designed to fit four different batteries, a Featherweight GPS, an Arduino Nano, a pressure sensor, a switch board, and two altimeters, all within less than a 10 x 10 x 10 cm volume.
   • This requires careful planning and a compact design to ensure all components fit without interfering with others.

   

   

   • While this is an extreme case, it illustrates how useful CAD is for optimizing space. We can also reduce this complexity by designing custom Printed Circuit Boards (PCBs) to minimize wiring and condense multiple functions into a single board.

2. Component-Specific Clearances and Orientation

   • Most electronics include solder joints, headers, and wiring, that extend beyond the component body and require extra clearance in the design. Take a look at the CAD of the Featherweight itself and notice the:
     • soldered components
     • holes for securing with screws
     • screw pins for wires
     • radio antenna

   

   • Overlooking aspects of the component is a common mistake and often leads to mounts that appear functional in CAD but do not accommodate wiring, connectors, and solder blobs once assembled.

3. Electrical Organization and Safety

   • A solid CAD model to organize electronics is just as important as an electrical diagram. We must ensure that components are placed logically and that wiring can be routed safely and securely in the real world.
   • We want to prevent pinching, shorting, and disconnecting of wires during launch and recovery.

4. Accessibility

   • Any design should ideally allow components to be tested and modified without tedious disassembly.
   • Accessible designs simplify integration of larger systems and reduce complications during assembly.

REMEMBER:

The importance of these factors extends well beyond electrical mounts. Whenever you design always consider how your design integrates with other systems, the constraints involved, and of course the functionality of the subsystem.