DIY+Switch-Adapted+Mouse

=DIY Switch-Adapted Mouse How-To =

 A switch-adapted mouse is usually the **second** kind of gadget that people build when they first start building assistive technology instead of buying.

Store-bought switch-adapted mice can cost about $50. Here's an example: [].

It's pretty quick and easy to build one yourself. You can find some how-tos on the internet that show how to add a 3.5mm jack to a mouse and wire it to the left-click switch (we only need left-click for the things we do in school).

Instead, I like to build them with an extra tail, with the jack on the end of a cable. For most mice, it's easier to find the space inside to route a cable than to install a jack, and it's more convenient for the user.

I use a cheap USB optical mouse ( [|here's some examples from newegg.com] ) and a cheap mono 3.5mm extension cable (a plug on one end and a jack on the other). Chop it in half, and you have about 3' of cable with a jack, and 3' of cable with a plug. You can use the plug later, when you make a switch.



Then open up the mouse (these pictures use a Microsoft mouse, but the generic cheap ones are amazingly similar in design). The screw is usually hidden under a label or a sticker. You can just punch through the label.



With the screw out, take the case apart. It might need a little jiggling, since most mice have some plastic tabs holding them together in front (where the switches are). We're going to solder the bare ends of the jack cable to the circuit board, to the contacts of the switch that is activated by the left button on the housing. First, strip the insulation off the end of the jack cable, and prepare the two conductors (the center wire and the shield). You need to 'tin' the wires.

If you need a good tutorial on soldering, go here: [] and then come back.



I just solder the prepared wire ends to the back of the PC board, at the 2 contacts of the switch. This is not really 'good practice', since the solder is providing all of the mechanical strength at the contacts, but it has worked well and it sure is easier than trying to get some pins in there. You could unsolder the switch and then through-hole solder the wires, but then you'd lose the ability to do a left-click at the mouse.

Now use a rotary tool (like a Dremel) to add some clearance for the extra cable. These pictures are Before (left) and After (right).



And then reassemble the mouse. As you finagle the front end into its tabs, you might find out you need more clearance on the cable notch, so more dremelling may be necessary.



Put the screw back in to hold it together, and you're done! It takes a sixth-grader about ten minutes to do this (after some practice), and the total parts cost is $5.

Links to other adapted mouse tutorials:

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