Electronic shifting servo mount (direct actuation)

The more successful cousin of the cable-actuated servo mount. Mounts directly to a regular road-style derailleur (think Shimano). Won't mount to Shimano mountain Shadow-style RDs, or funky SRAM RDs either. Can also mount to older Shimano STX-like RDs that stlil have a road-style parallelogram body.

There was a lot of flex in this system, so it definitely wasn't perfect. I think the barrel adjuster mount broke once.

I've ridden this before, & it was okay. A lot of improvements could be made both on the hardware & software side. I can't help you with the software side too much though.

Assembly & Materials

You must disable/cut the central spring or springs in the RD for this to work. You can use a medium strength servo with this. I recommend only using a single spring RD so you can actually disable/cut it.

Mounts by connecting to the barrel adjuster, & the horn actuates at the cable clamp.

It's important that the servo axis is positioned right over the top left pin on the parallelogram mechanism (if you're looking from the bottom of the derailleur, when it's mounted on the bike) to get the best results.

Updates

17 Dec 2016: Added images & other stuff to help visualize how the assembly comes together.