Final fabrication and circuit building

After finishing the second prototype, in the third and final prototype, I was trying to build the metal inner structure more reliable and more fit to the industrial design that I had sketched. 

  1. Bandsaw the aluminum sheet
  2. sand and polish the edge into the shape desired
  3. drill holes on sheet for fixing steppers and other mechanism onto it

Soldering, I am becoming master at this eventually. I was using stepper motor easy driver and screw terminals for reliability. Also, I was using hall effect sensor and tiny magnet for calibration. I attached hall effect sensor to the aluminum sheet and magnet onto the time-pulley gear. As a result, each digital has four wires from stepper, three wires from sensor, seven in total, which means, for the whole six digits, it's 7*6 = 42. 

In the video below you can see the first working prototype for calibration testing. It started from "B5" board and went back to "B5"  after flipping. 

I put all the circuit and electrical parts in box. Every time when I open it, either is for debuging it or checking which wire is loose... so I called it as my Pandora's Box.