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Picture of Minivac 601 (Version 1.0) Motorized Rotary Switch

This is the promised follow-up to my Minivac 601 Replica (Version 0.9) Instructable. This came together faster than anticipated and I'm pretty happy with the result. The Decimal Input-Output panel described here is a drop-in replacement for the manual version described in the Version 0.9 Instructable. As the title says it adds the motorized feature to the sixteen position rotary switch. As with the original Minivac 601 this is accomplished using a friction drive implementation. Here is a video of the Motorized Rotary Switch in action:

The new design begins with a more robust Rotary Switch using real bearings for a much smoother operation. One of the problems with the previous design was that the tolerances on the switch itself were pretty loose. As a result the motor required too much torque to turn the switch properly.

In addition with the new solenoid based design, the motor is only engaged when it is active. When not in use it is detached from the switch allowing for a great "feel" when operating the switch manually.

Step 1: Print the Parts

Print Resolution: .2 mm

Infill: 20%

Perimeters: 5 (All of the holes in the top panels should be very "robust" to support the soldering of parts.)

Filament: AMZ3D PLA in Black and White for the panel, any color(s) can be used for the interior parts

Notes: All parts were printed in PLA with no supports.The following parts are required for this Instructable:

  • 1 MV601 Decimal Input-Output Panel
  • 1 MV601 Friction Drive Motor Wheel
  • 1 MV601 Motor Mount
  • 1 RS Body
  • 1 RS Flywheel
  • 3 RS Gasket
  • 1 RS Knob
  • 1 RS Rotor
  • 1 RS Top
maewert6 days ago
I love this. I began reading the manuals from the first instructable and am so glad you completed the switch. Will be interesting to see if you can program it to perform anything useful, of course just the demonstration of the technology for historical purposes is useful, but you know what I mean. Are you thinking of resurrecting other computers? I've often thought it might be cool to replicate the PDP-11 code that the original hackers grew up on.
Best Wishes!
megardi (author)  maewert4 days ago
Thanks! Not sure if Tic-Tac-Toe constitutes "useful" but that's pretty much where the Minivac tops out. I don't know if you've see this video:

but one thought I have is to do something similar but as a "peripheral' device of some sort. There are some pretty cool PDP-11 emulators out there but I'm not sure replicating the hardware is in my wheelhouse. One device I am looking at right now is the Geniac:

rsumon2415 days ago
Your post is awesome this will be definitely help us, thanks jupiterfuture