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Picture of Mostly 3D Printed Rotary Switch

I am currently working on a replica of the Minivac 601, an electro-mechanical computer from 1961 (see the Wikipedia entry for details). For this project I require a rotary switch with the following characteristics:

  • 1P16T
  • Continuous Rotation
  • Non-Shorting
  • Panel Mount
  • Motorized

This last requirement is the kicker. Without having to drive the switch via a motor, a fair number of parts meet the remaining criteria. However I was unable to see how any of them could be easily motorized. Some are physically too small, and most require a fair amount of torque to switch between positions.

So I came up with the following 3D printable design that uses reed switches and magnets.

Step 1: Print the Parts

I printed the parts with the following settings:

Print Resolution: .2 mm

Infill: 20%

Filament: AMZ3D PLA

Notes: No supports

To make the basic rotary switch you need the following parts:

  • RS Body
  • RS Knob (optional)
  • RS Magnet Mount
  • RS Rotor Gasket (optional)
  • RS Rotor
rebeltaz5 months ago
This is a really cool idea. When you finish the minivac, will you be sharing your model/project so that us mere mortals can recreate one as well?
megardi (author)  rebeltaz18 days ago
megardi (author)  rebeltaz5 months ago
Thanks! As with my other projects for sure I’ll be sharing. I don’t want these great machines to be forgotten.
rnakamoto1318 days ago
This looks great!

Question: it looks like you managed to get some text on top of what looks like a 3D printed surface. How did you go about doing that?
megardi (author)  rnakamoto1318 days ago
The panel you are referring to was modeled in Fusion 360. The text tool was used to add the labels to the top of the panel, then they were extruded up .4 mm or so from the panel itself. Most single extruder 3D printers today (like the Prusa MK3) that I use allow you to add a pause in the print so that you can change filaments (M600 in gcode). I set a pause for the first layer with the text and switched from black to white filament. Works quite well. They are very durable. Hope this helps.
Please can you tell me in detail what this minivac 601 does and what are you going to achieve with it
Please can you also tell me about your idea and inspiration of making this because i am fascinated by your idea
Thanks in advance
megardi (author)  Sajal chuttani5 months ago
The Minivac 601 was a device for teaching computer concepts sold back in the early 60’s. You “program” it by connecting the various parts of the machine like lights, switches, and relays with wires. There were extensive instruction manuals teaching you about computer circuits and logic.
See the Wikipedia article for more details.

I’m am creating a replica of the Minivac 601 because they are becoming very hard to find and very expensive when you do (about $600 US on eBay). I want one and I think others might too. My other Instructables were done for the same reason.

In short I am trying to help preserve these wonderful devices.
Best of luck for your awesome project
Dont forget to put it on instructables
megardi (author)  Sajal chuttani5 months ago
Thank you. Keep an eye open for the Instructable in a couple of months.