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| Trackball Mouse Hack - Horizontal Axis Troubleshooting |
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| stimpyjoy:
I purchased a used trackball at http://www.ccagshow.com/ and have followed various tutorials to wire it through a PS/2 mouse to connect it to my computer. Tutorial Links for Reference: http://www.techdose.com/projects/Arcade-Trackball-Mouse-Hack/363/page1.html http://mamewah.mameworld.info/mousehack.htm http://www.willcoxonline.com/mame/controlpanel/controlpanel.htm The problem is that I am able to move the cursor vertically, but not horizontally. When I swap the wires so that the trackball Horizontal leads to the mouse Vertical and vice versa, I still only get vertical movement of the cursor. This leads me to believe that the trackball is working and there is something wrong with the mouse wiring. I have photographed and labeled all the wiring. Can anybody tell me what I might have done wrong? |
| NickG:
looks like your H2 trace is cut, check continuity to the IC. |
| PL1:
Have you used a cell phone/digital camera to check if the IR LED part of the optical circuit is working? (2 LEDs per axis) When you slowly turn the encoder wheel, does the voltage vary between high and low on both H1 and H2? Scott |
| stimpyjoy:
Thanks for the replies. This is my absolute first foray into electronics, so please forgive my ignorance. --- Quote from: NickG on August 11, 2014, 10:55:41 am ---looks like your H2 trace is cut, check continuity to the IC. --- End quote --- Can you actually see that from the photo? I'll check continuity when I get home. --- Quote from: PL1 on August 11, 2014, 02:15:33 pm ---Have you used a cell phone/digital camera to check if the IR LED part of the optical circuit is working? (2 LEDs per axis) --- End quote --- I didn't realize there were two LEDs per axis, but that makes sense. As you can see from the photos, I have removed the emitters and receivers from the mouse, so I assume you mean the trackball LEDs. I thought I had eliminated trackball error as a possibility by proving that either trackball axis can drive the cursor vertically when wired that way. Am I missing something? --- Quote from: PL1 on August 11, 2014, 02:15:33 pm ---When you slowly turn the encoder wheel, does the voltage vary between high and low on both H1 and H2? --- End quote --- I'm afraid this is way over my head. Can you tell me how exactly I can use my multimeter to check this? I want to learn but I'm a total noob. Thanks! |
| PL1:
--- Quote from: stimpyjoy on August 11, 2014, 05:47:15 pm --- --- Quote from: PL1 on August 11, 2014, 02:15:33 pm ---Have you used a cell phone/digital camera to check if the IR LED part of the optical circuit is working? (2 LEDs per axis) --- End quote --- I didn't realize there were two LEDs per axis, but that makes sense. As you can see from the photos, I have removed the emitters and receivers from the mouse, so I assume you mean the trackball LEDs. I thought I had eliminated trackball error as a possibility by proving that either trackball axis can drive the cursor vertically when wired that way. Am I missing something? --- End quote --- Sorry, mis-read that part of your post. :embarassed: The trackball part of the circuit does appear to be working fine. The thing to test is whether the signals from the trackball are making it to the IC on the mouse PCB or if one of the traces are shorted/open. --- Quote from: stimpyjoy on August 11, 2014, 05:47:15 pm --- --- Quote from: PL1 on August 11, 2014, 02:15:33 pm ---When you slowly turn the encoder wheel, does the voltage vary between high and low on both H1 and H2? --- End quote --- I'm afraid this is way over my head. Can you tell me how exactly I can use my multimeter to check this? I want to learn but I'm a total noob. --- End quote --- Standard IC layout is that if the "notch" on the IC is up, pin 1 is the upper left pin -- in your photo the notch is down, so pin 1 is the lower just above the "R3" label on the PCB. Set your multimeter to DC Volts. (5v range) Connect the black lead to ground, touch the red lead to IC pin 10 or 11 for the X-axis and pin 12 or 13 for the Y-axis -- see pgs. 5/6/17/20 of the datasheet here for the full pinout/description/electrical characteristics/schematic. As you slowly move the trackball, you will see the voltage increase/decrease as the teeth of the encoder wheel pass/block IR from the LED striking the photodiode sensor on the trackball PCB. Looks like the highs should be around 3.2v-3.8v and the lows should be around 1.2v-1.9v for the TP8452AP IC. (pg 17 of the datasheet) Compare the readings on the good axis to the bad axis. If one of the lines is stuck high, stuck low, or just not changing voltage like the other lines are, that will tell you where to look. If all 4 lines (X1, X, Y1, Y2) are good, the problem may be a damaged IC. :dunno Scott |
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