The idea is simple, take the scrolling mechanism out of a mouse, and move it to a large, heavy spinning wheel of some sort.  The benefits of this, scrolling long webpages and folders is tireless and editing video is a quicker process, as you are able to scrub easily and quickly.  The more you use a jog wheel, the quicker and more painless navigating and using a computer becomes.

You can buy jog wheels.  A popular consumer version is the Griffin Powermate.

 

There are two types of mice you will encounter and only one type will work for this project.

1. Mice with an electro-mechanical rotary encoder.  If you look at the inside of this type of mouse, you will see the scroll wheel turns a shaft that is mechanically measured for movement.  Usually it is a small box with wires or traces leading to it.

2. Mice with an optical encoder.  These are distinguished with an encoder wheel (it looks like a gear) on the axis of the scroll wheel.  When you scroll, the teeth of the gear interrupt an IR beam, and the mouse knows you are rotating the scroll wheel.  Therefore, you will also see an IR LED and a dark purple-black IR receiver.

 

We need the second type of mouse, with an optical encoder.

I removed the wheel and unsoldered the IR LED and receiver.  The IR receiver actually has two sensors, so it can detect which direction the scroll wheel is scrolling.  This is why there are three legs on the receiver.  Both devices have polarity, the receiver’s center pin is common.

 

 

 

This motor and HDD platter came from an old hard drive.  It already has mounting holes, which is very convenient.  There is an advantage to using a HDD platter over other spinning devices; it has terrific bearings, allowing low resistance spinning and is easy to mount.  There are a number of different mediums to use, including a VCR head, RC Car wheel, or a metal disk made on a lathe.

Note, the motor isn’t being used as motor, it simply acts as a spinning mount for the wheel.

 

 

 

This jar lid will be the optical encoding wheel.  I hollowed out the center and created teeth, so it can be mounted between the motor and platter.  The IR beam penetrated the black plastic, so I painted the teeth.

 

 

 

 

Here you can see the IR LED on the right (it blends in with the hot glue) and IR receiver on the left.  Both have been extended away from the board and hot glued into place ~1/4″ apart.  Test the alignment during this step, it needs to be relatively precise.

 

 

 

The home stretch.  I added a power indicator LED, a few strips of plastic to protect the encoder and a piece of wood to cover the remainder of the mouse.

 

 

 

And there you have it, a homemade DIY jog wheel!