>> It's going to be stationary actually. See, what I'm doing is mounting
>> the laser to the shaft of a stepper motor. Then I *very* slowly pan it
>> across a wall. Each 12 hour period the laser dot will make one trip from
>> one side of the wall to the other. The whole assembly is mounted into
>> the ceiling of a room and some control lines and power is run behind the
>> wall to a control panel somewhere. The only tricky part is microstepping
>> the motor for a sufficiently high resolution, I have a 400 step/rev
>> motor I'm using with 64x microstepping. Actual realised resolution seems
>> to be maybe 1600steps/rev.

How accurate does it have to be (as in f.s. and repeating) ? Gluing a 
small mirror on the bent needle of an analog meter should help you here. 
A 50uA f.s. scale meter would likely need only half that current on 
average. 25uA is very nice for battery power. The meter can be driven by 
a single PWM channel. It could work with about 18mAh for a month. Two AA 
cells contain a hundred times more energy than that.

Peter
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