I have a diecimila. The hardware page on arduino.cc says the I/O pins can handle a 40mA load, and the 3.3volt pin can handle a 50mA load.
Anyone know what load the 5v power pin can handle? The board would likely be powered by some battery setup totaling 12v or 9v.
Also, can I use the 9v and Gnd pins to power the board if I am powering from a battery, or do they have some diode protection or something? If so, I'd probably buy the power connector, but I'd rather not have to. Maybe I'd just solder to the tabs of the female power connector... we'll cross that bridge when we need to/if we have to.
In theory, the regulator can deliver 500mA. In reality, you may have power dissipation issues that cause it to overheat before that (power dissipated is ((Vin - 5) * I), which gets to be a significant number at 12V and .5A.)
Yes, you can power the Arduino via the 9V pins, and also Yes, this does bypass the diode protetection that is present on the DC connector (so don't connect it wrong, although I think this is somewhat less likely that using a PWR supply with backward connector.)
I am beginning to think that for high load currents on 5V, the thing to do is use a high-current regulated 5V power supply. These are a lot more common than they used to be (most cell phone chargers are about 5V, and most powered USB hub suppies are 5V at significant current.) For high powered battery apps, it may make sense to use a 5V regulator outside of the arduino board itself (where it can be heatsinked, for instance.) (And for 12V batteries, there are those charger adaptors for phones, or providing a USB jack for "generic charging of 5V things.")
Thanks! I have a few generic 5v chargers, mostly that small USB found on cameras and phones, but this is hopefully going to be an outside halloween decoration, away from any power outlets, so I am looking at wiring up 2 lantern batteries.
If I do that, I can split the LEDs among the two and wire them directly to the battery terminals, put the batteries in series to push up to 10-12ish volts and keep the voltage regulator spitting 5v into the AVR so things run smoothly, and not have to worry about heating up the voltage regulator. Only downside I see to this is that's a lot of wiring directly to the batteries...