I'm using the Centipede 64 I/O shield for my project. The shield supplies an area for adding a surface mount voltage regulator and capacitors. As I understand this is because driving a lot of leds will lead to higher current than the arduino and usb can handle, and I may have like 25 leds being lit at the same time, plus some buttons with pullup resitors, so there will be at least 600 mA if I'm not mistaken.
So I managed to figure out that SOT223 means how the component fits the soldering spots, and that xx mean voltage, and I want 5, so LM78M05 is what I'm looking for.
So, this is what I could dig up at my local supplier, 1A seems sufficient, will this work you think?
So, what about the capacitors, what values should they have? There are lots of opinions out there...
As long at it's SOT-223 and has the same pinout as the 78MXX SOT-223 variants, it will work fine. Fortunately the part you selected does have the correct pinout. You will need some external power source (otherwise having a separate regulator won't help), 6 to 9 volts would be ok. Some 10uF SMD capacitors in 1210 packages would work, though you can probably fit a wide range of capacitor styles on those pads. I went ahead and found you some 1210 ones from the same supplier: https://www.elfaelectronics.com/elfa3~ex_en/elfa/init.do?item=65-721-41&toc=18803
So I need an external supply of say 1A to power both the arduino and the shield.
I connect this to the arduino power plug, and then on the shield I change the pwr jumper, and then patch a cord from the Vin that is forwarded from the Arduino to the Vin next to the LM78 area? Will this do the trick macegr?
That's not a good idea, since the VIN pin goes through a protection diode on the Arduino. It's only rated for a few hundred mA, so you could burn it up eventually. You would connect the external power supply to the VIN and GND on the top of the Centipede Shield, then run a wire from OUT over to AUX, and switch the power jumper to AUX.