Comment on Pretty part of the week: Lian Xin XDMD camera autofocus coils

• unexposedhazard@discuss.tchncs.de ⁨2⁩ ⁨days⁩ ago

  I never worked with these before, but these coils are apparently called “Voice Coil Motors” (VCM). The one from this post is big but its the same tech that is used on a smaller scale in phones.

  I went and found a “driver” for these things and took a look at the datasheet to understand how it is typically controlled. This thing is 1.5mm x 0.8mm small so something you might actually find in a phone.

  www.ti.com/lit/ds/symlink/drv201.pdf#page=8

  The device is used to control the current in the voice coil motor (VCM). The current in the VCM generates a magnetic field which forces the lens stack connected to a spring to move. The VCM current and thus the lens position can be controlled via the I2C interface and an auto focus function can be implemented

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  • WaterWaiver@aussie.zone ⁨1⁩ ⁨day⁩ ago

    The ringing comp is interesting: it’s completely synthetic (sensorless). The chip models what it thinks the ringing should be based off some physical parameters (that can be configured over I2C), then drives the coil in a way that it hopes would counteract the ringing, but never actually knows if it has succeeded.

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