Happ trackball mouse hack -- Where to get 5v?

[compute]

I recently picked up an old Atari (Happ) trackball for a song, now I need to interface it to my computer.  I know that there are interfaces readily available, but I would like to try making my own.  Since the opto boards are still there, I know that I can just hack into those.  The first tutorial I found (http://www.mameworld.info/massive/How-to/Trackball_Hack/trackball_hack.html) involves getting +5v directly from the PC power supply, whereas any other (such as http://www.zumbrovalley.net/ArcadeOptics/trackball/) gets +5v from the mouse.  Does the mouse not get enough power to provide +5v for the opto boards?

[alfonzotan]

I recently picked up an old Atari (Happ) trackball for a song, now I need to interface it to my computer.  I know that there are interfaces readily available, but I would like to try making my own.  Since the opto boards are still there, I know that I can just hack into those.  The first tutorial I found (http://www.mameworld.info/massive/How-to/Trackball_Hack/trackball_hack.html) involves getting +5v directly from the PC power supply, whereas any other (such as http://www.zumbrovalley.net/ArcadeOptics/trackball/) gets +5v from the mouse.  Does the mouse not get enough power to provide +5v for the opto boards?

Using the mouse power is fine.  I've been running an old Happ trackball off a hacked USB mouse for a couple of years now.  No problems.

[PL1]

Does the mouse not get enough power to provide +5v for the opto boards?

The opto circuits are just a couple of LEDs and sensors.  No problem powering that with the mouse (which basically has the same LEDs and sensors), USB cable hack (which can handle more current draw), or power supply. (which can handle even more current draw)


Scott

[compute]

Ok, cool.  I figured as much, but I wanted to make sure that I wouldn't be losing reliability by getting power from the mouse.  I'll be removing the LED's and opto's on the mouse anyway, since they will no longer be needed.  Thanks for the feedback, guys!