How to make a switch adapted computer mouse

A switch adapted mouse allows your child to use a big button to activate software on your computer rather than the mouse itself.  I researched how to make my own switch adapted mice because the cheapest I could find online with specialist disability suppliers was $50AU plus postage.

I use a standard USB Logitech mouse, and a 3.5mm mono jack, 2 bits of wire, and some solder & soldering iron to make mine.  If you know how to solder, or your happy to learn, why not make your own with the following guide.  If you don’t have the ability to solder or don’t have time, I will be happy to sell one to you for only $25 plus postage and packing australia wide.

This modification isn’t dangerous because a USB mouse is only using a low voltage.  It gives your child the ability to press a switch, which tells the computer that you’ve clicked on the left mouse button.  There are lots of fabulous programs to download from the Priorywood in the UK which are listed on my Links page.  You could also create a powerpoint presentation with photos or a story, and the left click can turn the page, giving your child the ability to read a book (you can provide audio to play when the page it turned).

Disclaimer:  The instuctions below are provided as is, and I assume no liablility or responsibility for your safety while following them.  You use them as your own risk!  Please be aware that by modifying the mouse you will void the manuafactures warrenty.  Under no circumstances should you modify any item that can/will be connected to mains power.

To make the switch adapted mouse you will require the following items.

  • A standard mouse, a USB Optical is preferred, it can be second hand or new.
  • screw driver (usually a philips + but may vary with different manufacturers)
  • 6mm drill bit & drill
  • soldering iron and solder
  • multimeter to test for the correct points in the mouse
  • 3.5mm switch to test your work.
  • Marker pen

Step 1

Start by opening the mouse, usually by unscrewing a single screw the Logitech M90 I'm working on here then unclips from the front by sliding the top forward.  Take it apart, and put it back together a few times to make sure that you understand how the pieces go together.  Better to do it now so you understand the process rather than when wires and extra parts are placed inside.  You'll also get an idea about where to place the socket so it doesn't stop the mouse being reassembled.

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Step 2

With the board still in the mouse, mark a spot that the jack can fit into the side of the mouse without being in the way of the board or any components.

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Step 3

Take all the components our of the mouse base and drill a 6mm hole where the socket is to be placed.  Test for sizing.

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Step 4.

We want to adapt the left click so when you turn the board over your going to be working on the connectors on the right hand side (under the left microswitch).

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Turn the mouse circuit board over and use a multimeter set to continuity to determine what points activate during the switch.  Click here to learn how to test for continuity.  For the Logitech M90 there are 3 prongs on the microswitch, and we are only interested in 2.  Solder a wire to each, and leave enough length to return to the socket you've just drilled a whole for.

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Step 5.  Put the board back into the base of the mouse, ready to reassembled.  Find a suitable route for the wires to return to the jack without getting in the way of any components in the mouse, and make sure the board sits in it's original position.  Take the retaining nut off the threaded end of the jack, poke it though your drilled and and screw it back on to keep it in place.

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Solder the wires to the socket, this jack has 3 prongs, so solder on wire to the back, and on to the oposite side, and ignore the middle on.  It doesn't matter what wire is soldered to what prong, it will work either way, but the prongs must be correct for it to work.

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Step 6.  Replace the tracking wheel, and spring, and make sure the USB cable runs out the front as it did when you first opened it.

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Replace the cover and re-insert the screw.  The mouse should still function fully as a normal mouse, test all the buttons, mouse tracking and scroll wheel.  If there is problem check everything you've done, and that your soldering has short circuited the circuitboard.  Now the big test, insert a 3.5mm cable, and connect it to a known working switch (note if you are using a big mac type with audio, it will need to be turned on to test, with a battery installed) and see if it works.

If all that worked, your finished.  If it didn't work retrace your steps.  Check that wires are still attached, that your switch works with another toy or mouse, and that you haven't cross connected or damaged the circuit board when soldering the wires to the board.

Here's the finished mouse.

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Here's a link to some fantastic resources for your new switch adapted mouse.  Check our more in my links page under Switch Adapted Programs.

Priory Woods School - Great videos designed for switches & more

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