Motor is has a spindle with an O-ring around it for friction drive to the filter wheel. Small 1/16" diameter magnets are glued into holes in the filter wheel using a home made jig for location. Hall sensors sense magnetic fields so no physical connection between wheel and sensors.

Motor can slip under the posts and the spring fixed to the fixed posts supplies tension/force on the friction drive.

The wheel portion (that holds the filters) is actually flipped upside down from it's original configuration and the detente balls and springs removed so wheel is free to spin.

The 2 boards are screw mounted to the case using tapped holes in the case (small holes, like #1 screws ). Sensors are mounted over holes in the case (holes probably not needed in the aluminum) with slots milled to allow the sensor to get closer to the wheel (may also not be needed. Once working I'll "pot" the sensors in epoxy or similar.

Connection to the RPI (or other) is via USB to the Arduino Nano (skinny board shown).

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