Modular Peristaltic Pump Concept Tester

My first attempt at a 'budget' dosing peristaltic pump, mixing some design concepts together from some previous, related designs. You can find more info on the design, and I will be continuing to add related designs, here.One of the main concepts I was trying to test here was the use of bearing balls instead of the traditional full rolling element bearing for the contact with the tube.The other, was having this be a modular design that could be chained together with other components using the same stepper. The reasoning being to enable each section to have a different diameter of tubing, and therefore a different flow rate per step. This would make it easier to have the one pump handle the full range of desired tasks, from precision dosing of mL (or sub-mL) volumes to pumping at a rate sufficient to water a planter box at Liters per minutes.Ultimately the design didn't provide sufficient sealing with the spherical contacts to give the desired control over the flow. But I wanted to shar