user28773: I have a gear that needs to have roughly one rotation per day.  It does not have to be smooth or consistent.  So far, the best I have come up with is to have a stepper motor with an arduino that sleeps, wakes up once an hour maybe and turns the stepper a little bit.
Which arduino should I use for this and is there perhaps a simpler method?  Is there any way to fully cut power then when powered on the arduino advances the motor and then shuts off?
Any ideas?
I want to run off of a 9v battery and get as much time as possible.
edit: adding details as requested
the rotation needs to happen slowly over the 24 hour period.  The tube being turned is a light plastic 1" diameter tube that weighs about 2 lbs.

user313: Steppers require current - and power, due to I^2*R losses) to hold a position. Power off, they free-wheel. What kind of efficiency do you need? A stepper might not be the most power efficient.
An escapement permits or causes a gear to index one position and prevents it turning any farther. In a clock, it permits a weight-driven or spring-driven shaft to index. You'll probably want one that drives the shaft as well, probably with a solenoid. 
Another option that comes to mind and doesn't need an Arduino, is a clock motor. Gear down the hour hand 2:1 and you're done. Find a 24-hour clock motor and even that gearing will have been done for you.

28773: <p>I have a gear that needs to have roughly one rotation per day.  It does not have to be smooth or consistent.  So far, the best I have come up with is to have a stepper motor with an arduino that sleeps, wakes up once an hour maybe and turns the stepper a little bit.</p>

<p>Which arduino should I use for this and is there perhaps a simpler method?  Is there any way to fully cut power then when powered on the arduino advances the motor and then shuts off?</p>

<p>Any ideas?</p>

<p>I want to run off of a 9v battery and get as much time as possible.</p>

<p>edit: adding details as requested</p>

<p>the rotation needs to happen slowly over the 24 hour period.  The tube being turned is a light plastic 1" diameter tube that weighs about 2 lbs.</p>
 313: <p>Steppers require current - and power, due to I^2*R losses) to hold a position. Power off, they free-wheel. What kind of efficiency do you need? A stepper might not be the most power efficient.</p>

<p>An escapement permits or causes a gear to index one position and prevents it turning any farther. In a clock, it permits a weight-driven or spring-driven shaft to index. You'll probably want one that drives the shaft as well, probably with a solenoid. </p>

<p>Another option that comes to mind and doesn't need an Arduino, is a clock motor. Gear down the hour hand 2:1 and you're done. Find a 24-hour clock motor and even that gearing will have been done for you.</p>
