Trackball Mod part 1
Obscenely large trackball, $5. Obtain used USB ball mouse from fools at Goodwill, $3. Spending hours making something you don’t need, priceless. First I dismantled, cleaned and oiled giant trackball. Next I obtained working USB mouse with ball and dismantled it also. A mouse is basically an upside down trackball. The rotary encoders in the mouse are laid out in the same way in the trackball. The next step is to cut the two disks, from the mouse encoders, off their shafts, and mount them on the trackball shafts. After that, the hard part, remove both sensors and LEDs from mouse and mount onto new boards. Make mounting brackets, mount, and wire up. Test. Add two buttons. Test again. After the thing is working, then the case. Note the size difference in the trackball encoder disk and board compared to the mouse. I think that the proportions of ball to encoder rotation are about the same. In other words, if the mouse ball rolls four times to move the curser across the screen, so will the trackball’s ball.