Introduction: Mostly 3D Printed Rocker Switch

About: A retired software developer, living in Waterloo, Ontario, Canada, who appreciates having the time to make whatever the heck he damn well feels like!

The Instructable is a further exploration of what can be achieved with the humble magnetic reed switch and a few neodymium magnets. So far using reed switches and magnets I have designed the following:

For these builds, magnets are used to both actuate the reed switches and also to provide feedback to the user in the form of "stops" or "detents". In the case of the push button they replace a spring.

I believe you will find that feedback provided by the magnets is unexpectedly satisfying.

  • For the button, as you push the repelling magnets closer together, they push back harder much like a spring under tension would. The magnet implementation feels a bit "softer" at the beginning of the push which is not necessarily a bad thing.
  • In the case where we are creating detents by having strategically placed magnets attract the moveable slider or knob to predefined positions, the switches actually accelerate to those positions then stop quickly with a nice "thunk". Hard to explain but it feels great.

This Instructable will show you how to build your own ON-OFF-ON panel mounted rocker switch. The switch is almost entirely 3D printed with only a few easy to find additional parts required.


In addition to the 3D printed parts you will need:

  • 2 Reed Switches - Digi-Key part number 2010-1087-ND
  • 8 Disk Magnets - 6 mm (diameter) x 3 mm (height)
  • 6 M2 x 6 mm bolts
  • 2 feet 22 AWG solid core wire

Step 1: Print the Parts

I printed the parts with the following settings:

Print Resolution: .2 mm

Perimeters: 3

Infill: 20%

Filament: AMZ3D PLA

Notes: No supports. Print the parts in their default orientation.

To make the basic push button switch you will need the following:

  • 1 Rocker Switch Base
  • 1 Rocker Switch Front Plate
  • 1 Rocker Switch Rocker
  • 1 Rocker Switch Side

Step 2: Assemble the Parts

To assemble the Mostly 3D Printed Rocker Switch do the following:

  1. Insert three of the magnets into the Rocker Switch Base. The magnets should all be oriented with the same polarity, that is to say all sticking together when inserted. Mine friction fit pretty well, but use a bit of CA glue if they don't stay in securely on their own.
  2. While the magnetic reed switches are laying with the pins sticking up, solder two 22 AWG leads onto each. Use the second photo as a guide.
  3. Slide the reed switches into the slots provided with the leads running down the wire guides. See picture three.
  4. Attach the Rocker Switch Side panel to the Rocker Switch Base with 4 M2 x 6 mm bolts. They should self thread pretty easily.
  5. Attach the Rocker Switch Front Plate to the Base with 2 M2 x 6 mm bolts as in photo five above.
  6. Insert the five remaining magnets into the pockets of the Rocker Switch Rocker. Push them down as far as they will go. It's important that the polarity of all five is the same when facing out and that they attract the magnets in the Rocker Switch Base when inserted.
  7. Place the small printed "caps" into the pockets to hold the magnets in. Use a little glue if necessary.
  8. Insert the Rocker into the Base. It should just snap in and stay there. If it doesn't check the polarity of all your magnets.

That's it. You should now be able to switch between the left, center, and right positions. You should feel the three distinct detents (or stops) as you do so.

Step 3: Testing

I printed a little test stand, hooked the switch up to a power supply and a couple of LEDs, and made a litte video so that you could see and hear the rocker switch in action.

Step 4: Final Thoughts

Some people have asked, "Why do you do this? Buttons and switches are relatively cheap and readily available.".

This is true if I were starting a new project from scratch today. Figure out the design requirements, search online to obtain the appropriate parts, and then build around them. But mostly what I have been doing lately is making replicas of vintage computer related educational "toys" from the 50's and 60's. See some of my other Instructables for examples. In many cases the parts in question are no longer available.

Take my Minivac 601 Replica for example. The panel lights I found for it were not very similar to the original's, but I was able to 3D print "caps" for them that made them look pretty comparable. Finding a close match like that is rare though. Minivac 601 employed a motorized 16 position rotary switch for which I had no option but to design and build my own Mostly 3D Printed Rotary Switch. For a row of push buttons on the machine I used readily available arcade buttons which were the right color, red, but considerably larger than the original's. Now I can just build my own buttons (Mostly 3D Printed Push Button) tailored to the desired look and feel.

And now I have a workable and customizable rocker switch in my tool kit. When I look at the front panel of the PDP-8/I pictured above it makes me smile.

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