This iteration developed on the presence of test stations from the previous idea. The plan was to have a pseudo assembly line with separate points at which testing areas were placed. The difference was that the line would rotate in one place.

Advantages as compared from the previous iteration:

• More reliability on mechanical movement leading to less chances of failure.
• Less cuvette movement
• More control

Design thinking process:

• Mount motors onto a rotating pizza base type plate
• Mount up to 4 cuvettes on 1 motor
• Result would be capability to rotate independently twice
• Make stops along the circumference to imitate test stations
• Mount the bigger pizza base plate onto a ball bearing connected to a motor
• Mount all motor drivers on the underside of plate

(Images depict CAD design from different angles)

Advantages:

•  Limits cuvette movement
• Provides space for mounting electronics
• Test stations present in one plane so easier to design and place

Why the design failed:

• Biggest Issue: Wiring motors on a rotating structure causes unavoidable entanglement
• Very difficult to get plate stable 
• Motors used were inaccurate causing spillage and errors in test results
• Too much weight on one ball bearing (Big point of failure)
• 3D printed base was easy to break under load