Optical sensor

Optical Sensor

A simple FDM opto-interrupter module.

TO BE DEVELOPED.

Here's a picture of a commonly available optointerrupter, which is also a convenient size for most applications.

The arms extend out 10.5mm with a gap of 5.5mm. The arm width is 4.5mm.

The LED and photo-transistor are mounted inside the arms, facing towards each other through a narrow vertical slot. The slot width is approximately 1mm.

Although it looks fairly solid, it is actually just a thin plastic shell mounted over a small PCB. There are small plastic clips (just little square blocks really) inside the shell that allow the PCB to snap into place. The LED and photo-transistor are soldered into the PCB and extend up the arm approximately half way.

If we use common off-the-shelf parts, they may need to be bent to face each other, which would probably require fatter arms.