Using a trackball with a USB mouse control board

[rnoonan]

I bought one of the Ultimarc 2 1/4" trackballs with the plan to hook it up with a USB mouse control board that I got from Oscar Controls.  I hooked it up along with a spinner via a DPDT switch like I saw on the following page on Oscar's website:

http://www.oscarcontrols.com/DPDTswitch.shtml

It's pretty simple and the spinner works just fine.  Trouble is, the trackball doesn't work at all, not even the Y axis which is really simple.  Is it possible that the Ultimarc trackball is not compatible with a mouse controller?  The Oscar instructions use a Happ trackball, but I just figured all trackballs would use the same signalling.

Thanks for any help you can give me.

Bob

[rnoonan]

Well I answered my own question last night. I sat down with a scope and checked the spinner output vs. the trackball output. The trackball needs pullup resistors on the signal lines.

This morning I got an email from Andy @ Ultimarc saying the same thing. The value he suggests is 2K2. I used a 4.7K and it works fine.

Hope this helps someone else out,
Bob

[neuromancer]

Well I answered my own question last night. I sat down with a scope and checked the spinner output vs. the trackball output. The trackball needs pullup resistors on the signal lines.

That will probably come in handy -- I've got a trackball that I plan on hooking to a mouse. Where you you put the resistor?

Thanks,

(other) Bob

[rnoonan]

The bad news is that you need to take the whole thing apart.  The good news is that it is very easy to do that.  

There are two small circuit boards that the 4-wire connectors are on.  The outside two wires are +5V and GND, which are indicated by a + and - printed on the board.  The middle two are the signals.  Trace the signals to the pins of the optical device and you'll see a via by each one.  There is also one via for 5V.  I just put one thru-hole resistor connecting each signal to 5V using the vias (I used the 5V connector pin for the second signal since there is only one via).  Make sure you mount the resistor nice and flat against the board because it has to fit back in and there isn't much clearance.

Ultimarc said to use 2.2K ohm.  I used 4.7K since I didn't have that available.  I also originally tested with 10K and it worked fine.  The higher values just don't pull the signal up as high.

Good luck.

Bob