Team Unlimited (FVC 2013) designed and used a gear shifter in their competiton robot. We recently made a model of the shifter in Maya 8, and some pics are posted (or being posted) currently here in CD-Media. At the current time only this:
http://www.chiefdelphi.com/media/photos/28489
Photo is posted. More are being posted and should be up soon. Our team is posting some information on the shifter at our site:
http://eaglevex.syraweb.org
The information should be up in a day or two hopefully. There are some pictures of the prototype design are in the photo gallery on our site under summer projects.
UPDATE:
We got the information posted on our shifter.
It can be found here:
http://eaglevex.syraweb.org/GearShifter.htm
Some prototype designs can be seen here:
http://eaglevex.syraweb.org/MiscSummer2006.htm
And the robot can be found:
http://eaglevex.syraweb.org/QCC2006.htm
http://eaglevex.syraweb.org/Hartford2006.htm
For the shafter encoder, it is placed on the "block gear" (three wide gear) and it worked very well in autonomous. Hope our post on our site helps with any question, if you have any more question, you can PM, AIM or MSN me.
~Team Unlimited, FVC 2013