Introduction: Scroll-Wheel Hack
The scroll wheel inside my mouse is a very simple but brilliant mechanism that basically pushes two buttons in succession every time I scroll it fwd one click. The succession of the pressing of these two buttons is opposite if I scroll the wheel in the other direction. Thus it can tell which direction I am turning it and how far or fast I have turned it.
So I de-soldered this scroll wheel from my mouse and replaced it with two fabric buttons which I can now basically gallop on with my fingers to control the scrolling of my mouse and it is a very inconvenient action but I still think it is cool.
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Step 1: Materials and Tools
- Cheapest mouse you can find (hopefully it will be very similar to mine inside)
- Pen and paper
- Screw driver
- Soldering iron
- Helping hands
- De-solder or de-soldering tool
- Wire cutters
- Wire strippers
- Crocodile clips
Step 2: Open the Mouse
Unfortunately I used a mouse for this Instructable, which I had already disassembled ages ago and gotten rid of the outer shell.
But basically look for screws on the bottom of the mouse, they might be hidden under stickers or little stuck on feet. Make sure you get all the screws out and then the mouse should open nicely. Inside there will probably be more screws keeping the circuit board in place. I have learned that it is good practice to take photos of the circuit as soon as you have opened it because later on if wires come loose or you want to reverse your actions these photos will come in super handy!
So take photos and even notes.
Step 3: Locate Component
The photos I have only contain the main circuit with these main interface components:
- Left button
- Right button
- Scroll wheel button
- Scroll wheel turn 1
- Scroll wheel turn 2
- Optical position tracking (built into chip)
This Instructable only deals with the scroll wheel component that is the red little potentiometer-looking thing in the photos.
Check your circuit and pick out the scroll wheel component with its three legs. One going to plus and the other two going to two of the pins on the chip.
Now you will want to check if your scroll wheel component works the same way as mine. So plug in your mouse and measure the voltage running between the plus and each of the other legs of the components. Basically what you should see is that each time you scroll the wheel forwards one click you will turn on and off the flow of electricity between the plus and each of the other two legs. And if you turn your wheel slow enough you will see that on of them switches slightly before the other and in reverse if you turn it the other way.
I had to dislocate my scroll wheel component from the metal casing before I could actually de-solder it and then I was also able to de-solder the metal casing.
Step 4: Replace Component
Once you have removed the component you can replace the three connections with pieces of wire.
For this Instructable I use previously fabricated Three Fabric Buttons, which you can make yourself by following this Instructable >>
Or you can also hook up any other push buttons you have, but I think the fabric version will work best.
So you want to hook up the plus 5V from the mouse to the common side of both buttons and then hook up the other two wires to the other sides of each button.
Step 5: Finger Galloping
With the galloping you want to press down on one button and keep it down and then press down the other button so that both are pressed and then release the first button and then the second and then repeat.
And do this the opposite and you will scroll the opposite.