The first prototype ARPS circuits used rectangular tabs with 'mouse bites' (tiny holes) to connect the snap-off optical sensor modules to the main ARPS circuit. I wasn't happy with how difficult the modules were to snap off, and the fact that snapping the modules off often resulted in visible tearing of the fibreglass in either the board or the modules. Most annoying, though, was that after snapping the optical sensor modules off, the tabs that formerly connected them to the main circuit still remained attached to one of the separated boards, either the module or the circuit.

I revised the design using smaller, solid bridges and compared the process of snapping the modules off. The new design proved easier to snap apart and broke relatively cleanly in the middle of the bridges – and with fewer particles of board material being released in the process. Snapping the modules off did leave relatively sharp points at the bridges, but these were easy to trim off. What do you think? Is there a better option that makes it easy to distribute the boards in one piece and allows the modules to be easily and cleanly snapped apart?

New solid bridge design (left) and previous 'mouse bites' tab design (right).

The Gerber files with the new solid bridge design have now been added to this project.