Battery instead of USB?

[Awesome_Guy]

Is using an AAA battery connected to the TinkerKit inputs instead of connecting it to a PC, or Mac going to work with my Esplora Board?

[runaway_pancake]

An AAA battery?  
Well..., put it this way:
A battery pack of AAAs would work - or of whichever cells you like is fine - provided that's not greater than "5V" (or not greater than VUSB_MAX.)

[Awesome_Guy]

How many would there have to be in the pack? Five? Six? Twenty?

[runaway_pancake]

How many would there have to be in the pack? Five? Six? Twenty?

Yes, right, twenty.

If we're talking about alkaline AA, AAA, C, D cells (batteries), they're 1.5V each.
NiMH, NiCd are 1.2V or so each.
What to do, which to use, depends on what's to be accomplished.
With a "boost converter" and two AA batteries, you can get a lot of run time (I have.)
Be sure that the battery (external power) is disconnected from the Esplora whenever you have the Esplora connected to the computer.
http://www.ebay.com/itm/121142828799

[Isaac96]

Does the Esplora have a regulator?/

[runaway_pancake]

No, no on-board regulator; the plan was for the esplora-folk to stay tethered to the USB, happy to do game controllers and so on.
Maybe some of the stuff onboard gets a down-regulated voltage, but the "5V" is all straight USB.

[Isaac96]

Probably 3 AA batteries would be good. There is probably a 3.3V regulator on board for some things as Runaway Pancake said, and it might not work correctly at 3V.

[runaway_pancake]

There's probably nobody keeping up, but I've been doing some work with this because I picked up a TFT.



The Esplora temp_sensor IC seems sensitive to "V_in".

My test for the TFT was the temp_sensor / thermometer sketch, something meaningful with no extra parts needed.  I was using a lab supply set to 5V and then connected it to one of the little step-up converters I mentioned and my temp readings were about 4 degs F lower with it.  (Incr. V_in → decr. temp reading).  The step-up's O/P is 5.1V  The temp_sensor IC runs from 5V directly.

I have, definitely, ohmmed the pins out and the USB 5V pin is 0_ohms to the Tinkerkit 5V pins (and Gnd is Gnd).

> > > It's NOT the temp_sensor IC; it's stable. It's the ADC, its reference is "supply".

[AHippo]

The electromotive force is the difference between the equilibrium electrode potentials of the two electrodes. Taking a lead-acid battery as an example, E=Ф+0-Ф-0+RT/F*In(αH2SO4/αH2O). (HHR-210AB18F4)
Where: E-electromotive force
Ф+0--positive standard electrode potential, which is 1.690V
Ф-0--Negative standard electrode potential, which is -0.356V
R--general gas constant, which is 8.314
T--temperature, related to the temperature at which the battery is placed
F--Faraday constant, the value is 96485
αH2SO4--the activity of sulfuric acid, related to the concentration of sulfuric acid
αH2O--the activity of water, related to the concentration of sulfuric acid
As can be seen from the above formula, the standard electromotive force of the lead-acid battery is 1.690-(-0.0.356)=2.046V, so the nominal voltage of the battery is 2V. The electromotive force of a lead-acid battery is related to temperature and sulfuric acid concentration.