Lego Technic Sequential Stepper For 4 Speed Gearbox

Instructions for the gearbox:

https://www.youtube.com/watch?v=TfJJCuBwTQU

This video meant to demonstrate the stepper, not the gearbox. The nature of this design allows it to be used with almost any kind of gearboxes.
I'll make instructions for the gearbox later however I've been trying to show it from every angle in the video so you can attempt to reverse engineer it. It isn't that complicated.

Stepper:
I've got the inspiration from an other idea what Diederik van Leeuwen came up with. He goes by the name of Didumos69 on the Eurobricks forum. Click on the link below to see his post:

http://www.eurobricks.com/forum/index.php?showtopic=133743&st=175&hl=+degree%20+limite #entry2582304

The reliability of this stepper depends on the right rubber rings. For the limiter I was using the small lego silicone ring and for the stepper (the green ring) a non lego one that is much weaker than the white.
If it is too strong it pulls the knobwheel back instead of sliding trough on it when it returns to the basic position. So find the right combination by experimenting.

It requires the frictionless driving rings in the gearbox.
The motorisation can be solved by using PF medium motor combined with return to center mechanism too.

Sorry for the lack of quality, it was a hasty work. I hope the point I was gonna make gone trough. If there is any question, please use the comment section. I'll try to answer it as quick as I can.

Thanks for watching an reading.

Ps: There is a few failed changes in the video, those wre caused by applying shorter route on the handle. This design requires to be turned to the end point (about 65 degrees).