3D Printed AT Switches

This project is a great way to get those idle 3D Printers running and make something useful for AT Users in your community!

We’ve designed 3D Printed Switches that you can easily download and assemble.  This guide will show you how!  If you’re an AT User or part of an AT team (parent, SLP, ATP, etc.), bring this guide to your local STEM or Robotics team and they’ll know how to put it to good use.

(Note: This is a work in progress – we are posting it a bit early to support some of our STEM clubs who are working on this project!)

Skills, Tools and Stuff

To complete this project, you’ll need to know how to…

  • Print 3D Parts
  • Cut and strip wires
  • Test continuity with multimeter
  • Insulate wires with heat shrink tubing
  • Solder wires to switch tabs

You’ll need the following tools:

  • Soldering iron
  • Wire cutter
  • Wire Stripper
  • Multimeter with continuity test mode
  • Heat source for tubing (lighter)

In addition, you will need the following parts:

Downloading the Switch Files

Our AT Switches print in three parts: a Base, a Button Top, and a Bevel.  You can download all three STL files from Thingiverse:

3D Printed AT SwitchAT Switch (Mark I) on Thingiverse

Printing the Parts

These parts are fairly simple prints: make sure your bed is level because of the round bases (which sometimes give us trouble). A few other tips for printing these:

  • The parts orient the way you’d expect: the base is flat side down and the top and bevel are upside down (pointing up).  Basically put the largest flat area down
  • If you have supports turned on, you will need to remove the small supports from the threads.. these are not a problem and remove easily.
  • Threads don’t always look perfect, especially if you print at a lower resolution, but they will generally “clean themselves up” when threaded together.

Preparing the Cord

Preparing the cord is simple:

  1. Cut your 3.5mm Cord in half making cords for two switches.
  2. Strip back the outer sheath approximately 1.5-2 inches
  3. Separate the three conductors in the wire and use your Multimeter to determine which wire is the “tip” (see the video)
  4. Twist together the remaining wires (there will probably be just two, but perhaps 3)
  5. Tin both wires (incuding the one twisted together in step 4) with solder for later connection.

Soldering and Connecting the Switch

Make sure the cord is pulled through the hole and then tin both tabs.

Check the switch tabs to be sure you’re using the ones that will fit into the base.  See the video for details.

Solder both wires to the tabs – notice that because this is a simple switch, it doesn’t matter which tab gets which wire

Assembly

  1. Tie a knot in the cord to prevent it being pulled through the hole
  2. Add the spring to the button top.  You can shave the top stem down if you need more button throw.
  3. Screw the bevel into the base holding the button top in place

Testing

Your switch is now ready to use.  Any AT Adapted Toys can be controlled by this switch as can Speech Generating Devices, etc.