I am building a control for a spirits still using an Mega 2560. I have prototyped and tested the many small circuits used to control output devices and receive signals from input devices. While each circuit is relatively small, because of the numbers, I am hopeful of fitting them all on a single PCB board of around 9" by 11" or so. The Arduino will also be mounted on this board. I only need one circuit board, although I will probably make/buy two.
Years ago I made boards by manually laying out the circuit with black tape on clear sheet material that was used to make the PCB. Today I know one uses CAD software for circuit capture and PCB layout and the Gerber file can then be sent to a PCB manufacturer. Because I need only one big board, I am concerned about the learning curve for the CAD software and the possible high cost of having it made using the Gerber file. I probably would use the old method if I could find a source for the black tape and common parts templates, but I'm afraid they are no longer available.
I could use some advice on what might be the best approach for producing one relatively large PCB.