SparkFun Forums

[Nakor]

Hello,

I'm fairly new here and unfortunately I expect this question has already been asked many times. I have attempted to search for the answer but maybe it's so simple that it doesn't get asked often.

Anyway, I am building my first order and something isn't quite clear to me. I am picking up an Arduino, and as far as I know this can be powered through USB. I'm fairly certain that it can also power some things to the breadboard. I thought it would be wise however to pick up the breadboard power supply kit ( http://www.sparkfun.com/commerce/produc ... cts_id=114 ) and a wall wart. What isn't clear to me is what exactly I need.

Issue 1) Do I need the 5V, or the 9V? Keep in mind that I am just starting out and will (at least for the first month) be working mainly with an Arduino and breadboard. I learn very fast with this type of thing so I want to plan for expandability.

Issue 2) The wall warts (listed above) say that they are regulated. Do I even need the breadboard power supply kit? I suspect that I should have it as an extra precaution, but I'm just not sure. If I do need both the wall wart and the power supply kit, I'm thinking I should get the 9V and have the kit turn it down to 5V or 3.3V.

Any help here would be greatly appreciated

[anhingus]

if you want a choice of 5v or 3.3v go with the 9v wallwart.

voltage regulators are active voltage dividers and need an input higher than their output.

you can use a regulated wallwart to power a breadboard but the LM317 in the kit will give you better voltage regulation and less noise in your circuits.

usb is designed to provide limited power from your computer. a separate breadboard supply overcomes this limit.

[Nakor]

Ok thanks a lot. I'll go with the 9V and the power supply kit then.

[viskr]

Actually I'd recommend using a regulated 5V supply to start with. 5V has always been a standard, but with everything being powered from USB these days its even more of a standard. And now lots of regulated 5V wall worts are available, being driven by the move away from unregulated designs that consume more power when not in use.

SparkFun wall wort like this to start

http://www.sparkfun.com/commerce/produc ... ts_id=8269

Then all you need to is come up with a 3.3V regulator.

Most Arduinos and clones generate their own 3.3V from the 5V. Unless you need more than 100 mA or so most are adequate for that.

[Nakor]

Ok thanks for the information. My problem at the moment is I'm working with an extremely limited budget and I want to get what gives me the most options for the near future. I'm hoping to avoid the "Oops got the wrong thing!" situation. That is definitely good to know though.

[JoakimCh]

I agree with anhingus, you can then power your Arduino with it or any voltage regulator on a breadboard (and those in the kit). I found that kit quite handy btw.

[viskr]

For devices that can be powered from the USB, which most Arduino and Arduino clones can be, this is the cheapest way to go. And it will probably charge your cell phone too.

http://www.sparkfun.com/commerce/produc ... ts_id=9314