thanks for the clarification on bootloaders. As a novice, I will probably load a standard bootloader, whereas is sounds like you do some custom stuff there, right?
so I will stick to a mega as the main control board, that will be easy enough to upgrade in the future when ARM compatible grbl is more developed.
Seems like oscillators are kind of like a "reference frequency", but actually generating the cpu clock(s). I don't want any problems there, so not a problem to include the oscillator, just need to decide on which one, some are adjustable...dont think I need that, but there are 2500+ oscillator crystals in the 32.768 frequency on digikey and its like reading a foreign langue to me. SMD chips are strictly re flow right? SOJ seem like ones I can solder by hand? The there are 2, 3 & 4 lead packages. uggg makes my brain hurt.
on the encoders-- so to get the 4x resolution, you are registering both the rise & fall on two encoders. got it. I am going to pull the stages off tonight and come up with some of those measurements and I will update the math. The datasheet said 100khz max frequency, is that comparable to the 40khz trigger rate you refereed to?
ball screws --im glad you are as outraged as me. After I calmed down, I thought /looked at it some more...it seems they didn't use rear bearings in order to "cheat" on the travel. They get an extra couple inches where the bearing block would be. Not defending them, I still find it unacceptable, but at least I can see what they were thinking.
It was pretty close to a 1:1 belt drive to a lead screw replacing the steering rack. I had similar thoughts about the speed this motor would have been designed to do....slow, slight back and forth motion most of the time. but then when you turn, I'll bet that motor has got to drive it pretty fast. I am really interested to see what I can get out of them, speed, duty cycle, torque, ect. Also like to see if I can run them higher than the 12v they were designed for. The motors where $10 /ea, so I am good with taking some potentially destructive risks.However, if the motor was positively geared to the steering box, I suppose the commutation angle could have been deduced from the steering angle sensors.