I fabricated and installed the Azimuth and Elevation home sensors today. Optek OPB702D phot0-reflective Darlington sensers work well for this and are fairly small. A 0.250" hole was drilled into each of the 48T toothed belt pulleys and the sensor gets a reflection from the face of the pulley until the hole passes under it and the sensor output goes to logic high.

It may not be obvious from the drawings, but the area around the Az and El axes is really crowded. You can get a sense of that looking at the photo into the center of the tube. It took 3+ hours to get the brackets fabricated correctly and the mounting holes drilled in the body to hold them in place. In the process of doing this, I discovered that I had put the El axis 0.25" higher than designed when I drilled and slotted the body. It is possible that the Az belt is going to hit the El pulley as a result, and I will have to fabricate the body again. The belts should arrive early this week and I will know then. Heres to hoping...

The home sensor bracket design and installation was done directly with the hardware rather than drawn into the CAD drawing at the initial design time. If I did the CAD work in 3D, it is possible that I could have done this at the initial design time, but it was not obvious to me how it was going to fit until I had the parts made. CAD is good, but some stuff I just need to see in real life.