Logitech Mouse Hack - WHY don't they work?

[SirPeale]

I recently came across four PS/2 Logitech mice.  I figured I'd hack them for either future projects, or maybe sell them off.

I started with one (they're all identical) that didn't have a ball or ball cover.  After *finally* figuring out which traces were +5v and ground (I read a diagram backwards.  They're polar opposite on the pin chart) I cobbled it all together.

Plug it in and...nothing.  

I played with it a bit.  At one point I had it so if you spin the ball the pointer would go in a left-right direction faster than the eye can see.  

So what is it about Logitech mice that won't let them be hackable?

[Stormy151]

I got a Logitech mouse hack to work.

I bought a couple of HP branded USB mice from some surplus site for $3 a while back.  When I cracked the cases I discovered the circuit boards had LOGITECH printed on them.  Dissapointed, I decided to see if I could hack it- even though I had heard that Logitech hacks didn't work.

The IR detectors had 4 leads on them instead of the "usual" 3.  I managed to find a pinout for these on the website of the Seattle Robotics Society.  The topic was for extracting encoders from mice for use in home made robots.  The link is since dead, but I have scanned the diagram (I printed it out so I could use it on the workbench) I am hosting it here: http://members.cox.net/pbeals9/pics/encoder_pinout.jpg

Anyway, I wired it up according to the pinout and it works with my Betson/Imperial TB (which I actually got from you Peale, thanks!)  This diagram was the key.  It worked for me the first time,  though if I remember right, I think I had one of the axes hooked up backwards.  

The rest of the printing on the circuit board is M-UB48 Rev B   P/N 201137-0000, in case anyone is interested in finding the mice.  I don't remember what vendor I purchased them from unfortunately, but I found it through pricewatch.com.

Also, I think I posted about this when I first got it to work, I may have provided more info- but I'm too lazy to look for it right now.  I believe it was around March/April.

Hope this helps...  

[SirPeale]

Interesting.  My layout is standard, with the three legs on the receiver.  The center lead appears to be +5v, based on measurements from ground to that point.

Oh, and you're welcome.  

[Bgnome]

i also have a ps/2 logitech mouse hack with the standard 3 leg receiver/transmitters.  the middle leg was the 5v.  however, on my hack, i believe that the emitter actually looked like the detecter and vice versa, due to the little black plastic encasing being on the "wrong" one..

[SirPeale]

Don't think that's the case here.   The emitter is clearly an LED, and the receiver not.

[Grauwulf]

Thanks for figuring this out Stormy! I had an HP USB mouse here that I knew was a Logitech inside that I just wired to my Imperial 3" trackball and it works flawlessly.

[mh12]

The IR detectors had 4 leads on them instead of the "usual" 3.  I managed to find a pinout for these on the website of the Seattle Robotics Society.  The topic was for extracting encoders from mice for use in home made robots.  The link is since dead, but I have scanned the diagram (I printed it out so I could use it on the workbench) I am hosting it here: http://members.cox.net/pbeals9/pics/encoder_pinout.jpg

Does anyone still have this diagram? I can't find it anywhere. Nor can I find any tutorial dealing with 4-lead mice. I'm trying to hack a Logitech that sounds like this.. the number on it is 201106-0000.

[huygens]

Some mice (most logitechs as I understand it) drive the led with a high frequency pulsed signal rather than 5v DC. When you feed the mouse with the quadrature signal from your trackball / spinner it doesn't work as the signal is missing the high frequncy pulses the mouse expects.

Edit: Sorry, didn't notice how old the original thread was