Well, one could ask: Why is anybody asking such a weird question. Well. Thousands of million dollars, euros and remnibis are spend for cellphone research. Why not benefiting from an already existing technology and skip the step of inventing and developing anything from scratch?
In our optics-lab we have all the fancy microscopes to play with, but if it comes to add something new to it, one has to buy fancy adapters from one of the big lab-outfitter such as Thorlabs or Edmund. This is always expensive. Back in the days when I was a student I had no money and had to be creative to satisfy my creativity by taking off-the-shelf components laying in my backyard and build it. This hasn’t changed and thus I’m still trying to recreate existing technology for a cheap price – Science for a dime.
Many new cellphones have these optical image-stabilizers where the lens can not only be manipulated in Z-direction to focus the image onto the sensor, but also in X/Y translation to compensate for shakes from the photographer. This is done by moving the lens using voice coils. The lens is kept in a magnetic field, hold in place by little springs. Applying a current to the voicecoile, the electromagnetic field applies a force perpendicular to the cupper-windings and the entire lens is moved back/forth depending on the current.
Therefore we took an old audio amplifier and created a PCB:
The movement of the lens was actually characterized by a high-speed camera (IDS IX4) at 1800 fps. Therefore we illuminated the lens with a laser and captured the motion of the focus spot (center of mass) in X/Y direction. We controlled it by addressing a sinusoidal voltage signal (from an Android APP actually), amplified by an Audio-AMP and then sending it to the lens (setup on photos). The first result – as expected:
And the full movie from the acquisition sequence: