New car charger

Hi guys. Im just starting out with my arduino uno to make a "black box" for my truck. I want to record my trips and see if different ways are actually faster or not. The only thing is I don't know how im going to power my boards in my truck. SparkFun has had a car power power supply, TOL-09382, and I was hoping that someone here knows of a good place online to purchase one.

Thank you!

Look at cell phone chargers, cheap & plentiful.

One like this one? http://www.amazon.com/PowerLine-Universal-Adapter-Compatibility-90305/dp/B0042X8XOQ/ref=sr_1_3?ie=UTF8&qid=1340923050&sr=8-3&keywords=car+power+adapter+7.5v

It's a tad overkill with 2A, if you could find one with about 500mA would be nice. Stay away from USB ones, not enough juice. You need about +7V .. At any rate the one above will work for you.

-OR-

You could just simply tie into a constant +12V and ground. The external power is capable of 20VDC (MAX).. You might need a noise suppressor if you got alot noise coming through.

Hope this helps.

jcarmony:
if you could find one with about 500mA would be nice. Stay away from USB ones, not enough juice.

I'm not sure how you are misapplying the word "juice." The USB standard only provides 500mA of current and most cell phone supplies provide more than that.

jcarmony:
You need about +7V .. At any rate the one above will work for you.

7V (or more) is only required when powered through Vin or the barrel jack. It is perfectly acceptable to apply the 5volts from a USB-based supply to the USB Port or the 5V node of the Arduino.

In fact, I would suggest it is be preferred to power through the USB port since that would run current through the on-board poly-fuse.

It is perfectly acceptable to apply the 5volts from a USB-based supply to the USB Port or the 5V node of the Arduino

.

I would not say 'perfectly' .. according to the datasheet of the 5V regulator (NCP1117ST50T3G) on the Uno

5.0 V (Vin = 7.0 V, Iout = 10 mA, TA = 25 °C)
(Vin = 6.5 V to 12 V, Iout = 0 mA to 800 mA) (Note 4)

Anything less and your start drastically losing efficiency, and generating heat.
It's never good practice to apply source voltage the same as the regulator, yes it works, but it is not perfectly acceptable. And this is why power from a USB port is unreliable.

Therefore it is not a current issue, more a voltage (juice) issue (Which ironically turns into a current issue later when voltage is lost)

In fact, I would suggest it is be preferred to power through the USB port since that would run current through the on-board poly-fuse.

Most external car adapters should already be fused. Which is why I said the 2A version was overkill, and to find one rated around 500mA.
And it is really not a 'fuse', more of a device that limits current when heated (excess current) which adds resistance, it never actually 'blows'. Put it behind a 1A source and you will be fine. Put it behind a car battery and not so much.

jcarmony:
I would not say 'perfectly' .. according to the datasheet of the 5V regulator (NCP1117ST50T3G) on the Uno
...
And this is why power from a USB port is unreliable.

USB Port and 5V node do not go through the regulator.

Which is why it is perfectly acceptable to supply a regulated 5V to them.

You are correct. The regulator is for the barrel jack. I assumed the USB went to it as well. Yes, I know what they say about assume.
It is perfectly acceptable to power from USB. there I said it. I'll say it again.

It is perfectly acceptable to power from USB.