What I did this Weekend SCARA 28JBY STEPPER ARM

[Confus3d]

First time posting here. I am a long time viewer of the EEVblog. I wanted to share my project and the current problems it faces. A number of weeks ago I purchased a few cheep stepper motors of Ali-express. I know, all the good stories start with buying cheep items from the east. These motors are bipolar and tiny. For 1.5 USD I each they came with a ULN2003 stepper motor driver that is suppose to connect to the IO pins of a micro controller. I got the idea in my head Friday to model a SCARA like robot arm using these motors and little else. (Pictures Below) I tend to learn the same way I explore. By starting with very few materials or planning. Does anyone have and expirence with SCARA arms, printers, and plotters? If so what tips to you have for building or programming one. I aslo wondered if anyone know a way to use these motors or drivers with the Marlin Firmware? Has anyone had any experience with these motors? This is just a quick exploration of the kinimatics. If I like the deisgn I could scale it up to NEMA 17 motors and a dedicated trinamic TMC driver.