I need about 5-10 watts of 5V power to run various components of a project using a Decimalia.
I have a 5V DC supply that's rated for this load, but I'm wondering if this will interface with the arduino correctly. For example, if the power jumper is on USB power, but I feed 5V+ to the 5V pin, and the - of the supply to ground, will this back feed or do something unwanted? Directly powering the Arduino from the supply in at 5V end up with 3.4V on the 5V pin as mentioned in the wiki info.
Alternately, if I used a 12V DC supply into the supply plug and drew 5-10 watts on the 5V pin (1-2 amps), would that overpower the Arduino's converter? I don't see any specs for the max. draw from 5V.
If neither of these options are advised, what's the best option?
You might want to add a 100uf cap since when you pull the jumper you cut off the power supply filtering. I would also suggest a zener of slightly higher voltage to catch transients and a fuse.
OK. Now, is there a safe upper limit of power to draw from the 5V pin if I'm supplying voltage through the Arduino's power in plug (at either 9V or 12V)? I assume the Vin pin is were the higher voltage supply comes in without using the power in plug.
Decimilla has two regulators of different case styles that might go to 1.6a, 800ma each. I'm not sure since they have them in parallel and the data sheet is lacking.
Since it's easy to stick external power on something and regulators are cheap I'd suggest grabbing a wall wart at goodwill and building a regulator for it. Look at the NG schematic for one that does +5v.
I picked up a wall wart that only put out AC, 3 amps of it at 12V, w00t. Once rectified, filtered and regulated I should have as much +12 and +5 as I could want for most of the projects I'm considering. Since I also scavenge switchers from a variety of junk I have several that I can use. I'm not sure what to use the PTV one for since it wants to put out around 200vdc at 2+ amps but I'll think of something.
The diecimila schematic shows two regulators, but those are for "dual layout" on the PCB; you only get one of them on the final board (but you can pick one of two different packages.)
