Scroll-Wheel Hack




About: My work combines conductive materials and craft techniques to develop new styles of building electronics that emphasize materiality and process. I create working prototypes to demonstrate the kinds of electr...
Super inconvenient way to scroll though the web with galloping fingers on fabric buttons. (Smile)

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
- Multimeter
- 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

This can take some practice. Make sure that the scroll wheel is active in a window. In the video I was scrolling up and down a web page.
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.


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    32 Discussions

    Thanks for this. I've got a scroll wheel that has this 3 pin arrangement, and have spent the week-end trying to Google how the thing worked. (Most docs said the scrollwheel was an optical encoder)

    What I plan to do is build an autocue controller. Basically, the faster the 'clicks' are sent to the PC, the faster the browser page will scroll, and vice versa. The 'clicks' will be controlled via a 555 timer and an inverted signal, (thus will have the flip-flop arrangement to emulate two switch presses) The timer will be controlled via a preset connected to a knob held between thumb and forefinger. Turn one way to speed up page, and opposite to slow.

    Now it's just a question of thinking of a system to decide clockwise (up) or opposite.


    10 years ago on Introduction

    Hmm... this is only good for nervous people. *tapping fingers*


    10 years ago on Introduction

    Pretty useless :) . Why not just wire a small motor to the mouse which turns the mousewheel like a gear controlled by the buttons?

    4 replies
    AzaylesLance Mt.

    Reply 10 years ago on Introduction

    Fix the original scroll wheel encoder to a hamster wheel, poll the wheel rotations in software and see how fast the hamster's running - and in which direction :-D


    10 years ago on Introduction

    to make somthing useful i think this project would mix together nicely
    with the hard drive dj project
    ...this would eliminate the micro controller portion of the dj project and all the software

    hard drive dj project


    10 years ago on Step 3

    That has to be the only mouse I have ever seen that has an normal encoder instead of LED encoder.

    3 replies

    yep rotary ENCOder scroll wheels can be found on many different brands and at surprising price points. It's completely up to the manufacturer whether they install IR or rotary, whichever happened to be cheaper at the time most probably! Optical can get bits of cat hair in the gears and rotary can loose its accuracy over time.


    10 years ago on Introduction

    yeah this seem kind of time consuming for a scroll wheel even though it looks cool... you could change the scroll rate though!


    10 years ago on Introduction

    Ouch, either you weren't endowed with too much coordination or something but that looks extremely time consuming even if you were to up the lines-per-scroll number. Doesn't it get annoying after a while by the way? An innovative idea,... just that there has to be a simpler (and cooler) way to use what you've learned.

    2 replies

    Reply 10 years ago on Introduction

    I think part of the idea is that it is kind of backwards and not innovative and useless and still kind of cool at the same time...


    Reply 10 years ago on Introduction

    Oh okay,... if you were just having fun with it it's cool. And btw, thanks; dint know about the micro switches and what not so you saved me having to screw up a mouse to find out. Now at least i'd know what to expect if i ever opened one up :)


    10 years ago on Introduction

    i know this is a strange idea but could you set up a switch for up that auto gallops up and down does down? I am pretty new to electronics but its a thought!


    10 years ago on Introduction

    That has to be one of most inefficient-yet-cool instructables I've ever seen. Interesting idea, but very impractical.