I'm trying to create a shield to measure current on the various legs of a standard PC ATX power supply. I've found a handy part from Sparkfun (http://www.sparkfun.com/products/9498) to bring the power onto the shield, but it's rather large and wouldn't leave much room for anything else on a standard sized Mega Shield. I was wondering if there's any reason to avoid creating an oversized shield, I haven't yet purchased an Arduino Mega, so I'm not sure about any potential clearance issues (specifically the USB cable). Additionally, it seems most PCB fabs offer better pricing on plain rectangular boards, versus something like an Arduino.
That connector is almost exactly the same width as a Mega, from what I can see it will fit very nicely over the DC and USB jacks as the pins are set about 14mm back from the edge and they will sit nicely between the jacks and the headers.
So I think it’s a very good match and you shouldn’t need to go for a larger board.
Having said that I don’t think there’s any real reason not to.
Well, the reason I was thinking of making the board larger is to put a second connector on, to a "funny" cable to actually power the PC. It's certainly not something that would pass any specs, but it's a simple and easy way to get power off the shield.
The power flow would be something like this:
PC Power Supply --> My Shield --> PC Motherboard
As far as number of inputs goes, I have 10 inputs, V & I for 3.3V, 5V, 5V Standby, 12V & -12V. I suppose I could multiplex the analog inputs myself, but it seemed silly to not just buy a Mega that does this for me, and allows for more options on future projects.
make sure your shield tracks are wide enough to carry the current!
Or act as fuses, right? :roll_eyes:
hee hee smelly smoky ones!