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Topic: Oversized Mega Shield (Read 755 times) previous topic - next topic

iwoloschin

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.

Graynomad

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.

______
Rob
Rob Gray aka the GRAYnomad www.robgray.com

iwoloschin

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.

mmcp42

make sure your shield tracks are wide enough to carry the current!
there are only 10 types of people
them that understands binary
and them that doesn't

iwoloschin

Or act as fuses, right?  :smiley-roll:

mmcp42

hee hee smelly smoky ones!
there are only 10 types of people
them that understands binary
and them that doesn't

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