Drive 1W LEDs from batteries

CrossRoads:
Look into constant current drivers vs straight voltage with current limit resistor.

That's what I'm looking for but all the modules I can find are either 12V or 85-240V inputs. What I want must exist judging by the number of cheap flashlights that use a single cell to power a 1W LED. I've spent a while with google, deal extreme, and aliexpress, but if you can point me in the right direction it would be helpful.

johnwasser:
You can use an LM317 Adjustable Voltage Regulator as a constant current driver. Google: LM317 constant current

I understand these require at least 3 volts higher in than out even as a constant currant driver and as linear regulators just dissipate the extra power, so they're not very good for battery powered circuits.

cjdelphi:
cheapest solution would be a 555 chip as PWM ..... that way a small potentiometer could be used to vary the brightness.

I'm not sure what you're suggesting. I don't need to vary the brightness, I'm looking for a power driver. A 555 can not supply 350mA (a quick search seems to show 200mA, 600mW), and it's not cheaper than using a PWM pin on the arduino that's already controlling the project.