When designing an add-on for an existing system:
- Make a thorough list of what you wish to achieve.
- Make a thorough list of resources, such as memory size, physical size, of all relevant components.
- Gather relevant software libraries or equivalents, and make sure minimum size requirements are met.
- If size requirements are not met, see if you are able to work around the problem through working “closer to the metal”.
- When size requirements are met, begin design of schematics / preliminary physical model.
- Iterate 3-5.
When designing an electrical circuit, either when prototyping or designing a footprint for electrical CAD software, or when designing an enclosure, make sure to have reference parts, both in order to take accurate measurements, and to determine the direction of wires or pins protruding from said connector. Spacing between parts and connectors is important, as well as placement of connectors on board or panel. A mock-up of the assembly will most likely be a sure-fire way to avert future mistakes and valuable time invested in correction.