I need advice for which batteries to use (and if I will then need a voltage regulator or not.) This project is extremely important to me. (Its my first big electronics project ever. I'd really appreciate the assistance.
I'm building an ATmega328 powered LED PWM circuit with 6 PWM channels.
I have to build this device as small as possible, but to run as bright as possible for as close to an hour as I can get (or higher)
I basically have the same setup as http://fritzing.org/projects/arduino-knight-rider-with-8-blue-12v-led-modules/
except I'm only using 6 Leds (or 12 (2 per channel)) and my leds are different. I'm looking at using these leds:http://www.sparkfun.com/categories/173
Which run at 60-75ma) with a forward voltage of 3.0-3.4 volts. Obviously I will not use the 12 source like in the link. I need to figure out my own source.
I need to use rechargeable batteries, so I've narrowed it down to dealextreme.com's 3.7 volt or 3.0 volt CR123A's or the 3.7 18650. (I want it to be as small as possible, but still have near an hour of battery life.)
I'm really desiring a consistent accurate PWM in my circuit, but I don't know what do do about the batteries and voltage regulator...
Should I use 1 CR123A? 2 CR123A's in series? in parallel? 3.0volt? 3.7volt?
Or should I use the 18650 3.7 volt battery? or 2? series/parallel?
then based on my battery choice will I need a voltage regulator? which one?
Also should I be powering 6 leds? or 12 (6 sets of 2 in series)?
Thanks for reading this!
If you need more information I will gladly respond quickly!