I'm trying to put together a training device that I can include in the
cost of a seminar, $36 is more than 1/3 of the worst-case BOM cost that I
was contemplating. I need to know if I can beat this down by being
creative, if I need to bite the bullet and accept a higher BOM cost, or
if I should yank my eldest out of school and put him to work in the
garage bending metal!

The principal of this thing is that there's a counterweighted arm that
swings on a shaft that's pivoted on bearings in the large holes in the
frame. A microprocessor monitors the position of the shaft through a
potentiometer and controls the voltage to a motor/propeller, with the
goal of holding the arm at a commanded position. The hole locations are
assumed to need tight tolerancing because of the apparent tolerance needs
of the pot I'm planning to use, but I'll be re-thinking that decision
here soon.


Hi, Tim.
You have investigated fabricating your device from scratch. Have you
considered going the other way? Take a square or rectangular tube of
the size you need and cut it to the shape you need. Add two spacers
screwed to the walls so when you machine away the top, the sides
remain parallel. Simple to make and the wall thickness is whatever you
need. Perhaps you can find an aluminum extrusion that will be the
basis of the structure.

And don't ask us to place that sensor on a circuit board for you. The
specs look like pure smoke and mirrors. If you let it out of the box,
it will die!

Paul
Redmond, Oregon

Thanks in advance.