Hi, I received the DFRobot Mega Proto Shield today amongst some other bits and bobs. Thanks! However while looking over the board and comparing its header footprint to other gear I’ve realised that there seems to be some pretty major pin alignment issues. I compared the header pin footprint to: arduino Mega 2560 clone; arduino due original; arduino proto shield mega R3. I found that:
the DFRobot shield is too wide (55mm) - one row of pins is outside the target area. This would seem to be just an error?
the DFRobot shield is longer than expected (108mm). The pin header for pins 22 through 53, aligns but only on the inner set, leaving the matching shield connections outboard of the pin header. Seems odd?
The width issue would make the board unusable I think. Am I missing something?
Regards, Rowan Patterson
Update: Photo of the Arduino shield on top of the DFRobot shield, on a light box to show pin alignment.
It’s not entirely clear from the image, but typically the row of pins ‘outside’ the target is matched by a similar row on the other edge that is ‘inside’ the target. This means that you can insert headers on the top side, alongside the pins on the bottom side, to create a stackable shield. The extra length accommodates extra pinouts, convenient for off-board connections. The board cannot be made stackable for these pins. These could be cut off if not required.
Thanks for your reply. Yes I agree (somewhat) in general, but I think the problem I’m describing is unresolved. I suggest having a look at a physical example of the board and compare it to some other mega/due footprint kit. Something is wrong. Only the connecters on one of the long sides at a time can be inboard (adjacent to the prototyping area) all other pin connectors must then be outboard (i.e., the other long side, and pins 22-53). I think it’s safe to say that generally the breakouts from shield pin headers are wanted to be easily accessible from the prototyping area rather than outboard? I’ve attached some additional photos of the shield loosely placed on header pins connected to an Arduino Due.
That style is not stackable because the breakouts from the pins are all on the inner side. The best option would be to have another set of breakouts third row in from the right in your first photo, so that one set can be offset for stacking and one set available for direct wiring. But that’s not the way that your board has been designed.
