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Looking for a way to shift a 30mm lens in two axis perpendicular to another lens. The lens is for shifting a video projection up, down, left, right. Basically what you will find in tilt-shift camera lenses or video projectors with motorized lens-shift feature.

The travel distance is very short, 1/4th of the 30mm lens diameter, but precision has to be at least 1024 steps across that 30mm/4 length.

Would love any ideas how to implement this. Can only think of a gantry based system but can’t find small enough motors. Speed is also a concern, needs to go from one edge to the next in 1/3 seconds.

Haven’t been able to teardown tilt-shift camera lenses or motorized video projectors to see how it is implemented there.

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    $\begingroup$ Look for piezoelectric actuators. They are used in most professional camera/video equipment as the provide very fine resolution combined with high self-locking moment when at rest. If you want to move very often and very fast, voice-coil actuators might be an alternative but they lack any self-locking moment when not powered and controlled. How much force is required to move your lens? $\endgroup$
    – JLo
    Feb 13, 2018 at 21:47
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    $\begingroup$ not much. How about the stepper motor screw drives from CD/DVD drives? $\endgroup$
    – Mark Legault
    Feb 14, 2018 at 22:42
  • $\begingroup$ Could work, could not work. It's difficult to give substantial answers to your problem unless you provide more numbers and calculations. $\endgroup$
    – JLo
    Feb 15, 2018 at 7:03
  • $\begingroup$ the weight it is supposed to move is 50 grams. Not sure what calculations I have to provide though $\endgroup$
    – Mark Legault
    Feb 15, 2018 at 11:10
  • $\begingroup$ 7.5mm travel distance, nearly insignificant force/torque, at least 1024 steps - I'd say it's enough of numerical data. Piezzo have way too small travel distance. I'd go with steppers and screw actuators as they are easy to work with, although you may choose galvos, which should be more graceful if harder to implement, or if you're feeling very ambitious, ultrasound motors. $\endgroup$
    – SF.
    May 15, 2018 at 15:26

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An easy solution is to use a Motorized Linear Slide Pot - they're not expensive and they have a motor and a pot - you still need to build the feedback loop to control the position and use a DAC to provide a voltage for the setpoint. A mechanical linkage can reduce the range of motion to what you require.

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Well, a lever controlled by a fine thread which can be rotated by a stepper motor. Something like this but you will have to deal with the rotation arc etc:

enter image description here

The ratio of the distances "pivot : connection" and "pivot : thread drive" will give you the 4:1 bit you are after.

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A radial solution seems the best idea to step 2.8 times in every degree. An epicyclic gear agreement could pivot the lense through the required range by creating an offset centre fulcrum. The best part of this idea is that the lense itself could be a gear in the system.

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