Other points of note are that the mounting bracket is customised for the aluminium handle of a Printrbot Simple Metal and so you will need to design a mount for your own printer model. UserUnrelated has designed the baseplate so that a mounting bracket can easily fit it. Just design your own.
To complete the model you will also need elastic bands, some bolts and a hole reamer. in the original 1/4 inch shoulder bolts were used. A elastic band will need to be cut and glued to the counter gear for the mechanism to work.
So in short this is definitely a work in progress and it will need adapting to your 3D printer and to your rotary counter. Worth a try as it is a very good idea, which is why we have listed it even though it needs some polishing.
As always we would be very interested to know how you get on and especially in adaptations that mean that it will fit more commonly available mechanical counters.