The ordinary joint controller is build with a usual electric coil and a permanent magnet, that is turing the rails. It really fast, but not really powerful. Just a little piece of gravel is prohibiting its functionality. The resultis really frustrating. So I decided to change this behaviour.

First idea was to use a servo, but the creation of a PWM signal for its control is simply too complicated. So why not usinga simple electric motor with a micro gearbox? Well – that sounds perfect. DC motors are able to spin in both directions. I found a DC motor in an electronic online shop with an integrated 1:1000 gearbox. Next step is to establish an automatic end switch for both directions. I found a great circuit digram in the net. So with some patience I used to original case and replaced to content.