DIY rotary encoder

This is quadrature rotary encoder which allow measure speed (rotation) and direction.

Used parts:

• 2x Optical sensors like this
• 2x 626ZZ bearings
• 3x still smooth rods 2 mm diameter and 20mm length (part of nail)
• 1x M6x70 bolt [DIN933]
• 3x M6 [DIN934]
• 3x 4.2x16 [DIN968] to mount

Many plastics transparent for IR. I solve this problem by aluminum foil with glue (on photo middle part of process).