Motors for a project?

[LifeForce4]

I'm going to start a project where I need to have movement be precise. It's pointing a laser and it's movements need to be at a steady interval (thought of stepper motors but didn't know if that would not matter).

Should I attempt to use brushed motors or would stepper motors be better?

Thanks,

 

[Reloadron]

Figure it this way. Stepper motors rotate X number of degrees per step and many can do 1/2 steps. So I have a stepper motor lying here that does 1.8 degrees per step. That is 200 steps per full 360 degree revolution and 400 half steps. The half steps being .9 degree steps or 54 minuets of arc. If I run the motor into a good precision gearbox I can get pretty tight. So how good do you want in the arc?

Ron

 

[picbits]

Have you considered mirrors attached to a voice coil type arrangement rather than motors ?

Most laser lenses contain voice coils and some nice strong magnets for positioning the lenses - shouldn't be that hard to use them for mirrors.

 

[LifeForce4]

I haven't calculated how many minutes or seconds I need in the arc I'll be doing that next. I completely forgot about the gearing will help with the precision. I am planning on having the end point, dot of the laser, being accurate within 6.5mm(0.25in) at about 3m(10ft). I'm not 100% sure where to find any information on using a lense/voice coil setup, a stepper motor should be good enough I think and easier to work with (no experience though with voice coils).

Thanks for the help and tips.

 

[alec_t]

You've stated the accuracy (6mm @ 3m) but what angular range will the laser have to move through?

 

[LifeForce4]

The x-axis will be 38-45 degrees and the y-axis should be no more then 65 degrees. Those are the extremes of the angles that it will need to move in.