A while back, I would use a 5V regulator and a 9V battery for extra power on the go; like to rech...

[G+_Robert Hafer]

A while back, I would use a 5V regulator and a 9V battery for extra power on the go; like to recharge my Palm 3. Is the power from that "clean" enough to run a remote Arduino and sensor?

[G+_Eddie Foy]

If a 7805 yes, but do use the filtering caps in the datasheet.

[G+_james robinson (radiati]

Any battery is "clean", it's as DC as you can get.

[G+_james robinson (radiati]

Just get dollar store auto phone charger. I use them all the time. 6-20 vdc in, 5vdc out. Easy and cheap

[G+_Eddie Foy]

Not necessarily, switching regulators are rather noisy.

[G+_Stede Bonnett]

You will dissipate a lot of power in the regulator. If your sensors are up to it you would be better off with 3xAA Alkaline =4.5V or 4xAA NiMH =4.8V (LSD ones like Eneloop's).

With those you can drive the 5V pin directly. This also bypasses any regulators on the board that you would find in an 'off-the-shelf' Arduino, saving even more energy.

Also, many sensors operate at ~3.3V and you can use 3xAA NiMH or a 1S LiPo (or coin cell or CR123A) combined with boards designed to run at 3-3.3V.

There are years worth of posts at http://jeelabs.org/ on this topic.