Interfacing the trackball

As I mentioned earlier, I needed to use a PS/2 mouse to interface the trackball to the computer.
I bought a cheap mouse off the net at Geeks.com
Here is a picture of the mouse, with the top removed.


I then removed the circuit board. (The rest I threw in the garbage.)



I then removed the led emitters, the receivers, and the micro switches that the mouse buttons activate. This mouse has a plug on the cord that plugs into the circuit board, I unplugged it to make the operation a little easier. I used a soldering gun and solder wick to un-solder the components. The solder wick is pictured above the mouse components.
This mouse didnt have a scroll wheel, so there are only two led emitters and two receivers.
These parts are below the solder wick, also the two micro switches.
I then soldered two wires into the holes in the board where the receiver's outside leads soldered to, for a total of 4 wires that will attach to the trackball.
I then found the 5VDC points on the board and soldered two wires to those.
I then soldered 2 wires in the holes that the mouse button switches were in, for a total of 4 wires which will attach to the mouse click buttons on the control panel.
I wound up with 10 wires coming from the mouse board.
I then attached the receiver wires to the green, blue, yellow, and purple wires of the trackball.
Then I attached the 5VDC wires to the red and black wires of the trackball. This supplies the trackball with the power it needs to work.

I then re-connected the mouse cable to the board, plugged it into the PC and tested it.
The mouse arrow (on the computer screen) has to move up and down and left and right when you move the trackball.
It it doesnt move in sync with the trackball movements, you will have to swap the 4 receiver wires around until it does move right.
After it tested OK, I soldered all connections and insulated with heat shrink tubing.
I then attached the board to the trackball by clamping the mouse wires with a plastic clamp.
I also used a plastic wire tie to hold the mouse board to the trackball LED board.
Here is a pic.

I know this is very sketchy. I may go more in depth with the mouse hack later.
If you want to hack a mouse, search for how to do it on the web.
I also suggest that you read up on how a mouse works, so that you will understand what is going on.
I have also found that not all mice are suitable for hacking to a trackball.
The receivers have 3 leads. For the mouse to work, each outside lead of the receiver must go back to a pin on the integrated circuit (chip) on the mouse board.
I have found some mouse boards where the center lead goes back to the chip, and the outside leads go to power + and -. These chips will not work.
If you turn the circuit board upside down and follow the traces you can tell how the receivers connect. I think that a chip with the number 361125-0000 (made by Logitech) will not work. I cant find any datasheets on this chip, but it looks like to me that the recievers have only one lead going back to the chip.

Before you hack the mouse, I highly suggest that you study the way the receivers wire up.
You can get the number off the chip and search for a datasheet on the web.
A datasheet should tell you how the chip connects to the receivers.

Here is the number on the chip that I used:
(Genius) k0307057 2k337b13
I also have this chip and plan to use it on my next hack, Im pretty sure it will work:
ec3592re (probably generic, I cant find a manufacturer name).
This is the chip in the pictures above. I bought 3 cheap mice for hacking.

The mouse does not need a scroll wheel, but if it has one, just unsolder the emitter for the scroll wheel, dont unsolder the receiver or the micro switch for the scroll wheel.
I would leave the scroll wheel receiver in the board, just to prevent the chip from receiving any false noise signals. I would unsolder all the emitters, just to cut down on the total current draw, because the trackball will draw some, and Im not sure how much current the computer's PS/2 mouse connector is good for.

Like I said earlier, I may go more in depth on how to hack a mouse.
But for now this should give you an idea of what I had to do.

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