For my end goal, I needed a mechanism that could by continuously rotated at a constant angular velocity. To satisfy this requirement, I used the Grashof equation for my mechanism by thinking of my mechanism as two four bar linkages.
L + S < Q + P (Grashof Equation)
This tells us that if the longest and shortest link lengths are less than the remaining link lengths, the linkage is a Class 1 case. Therefore the linkage has one grounded link that can rotate fully. To ensure that my input link could rotate fully, I adjusted the link lengths such that the four bar linkage satisfied the Grashof condition.
Figure 1: First four bar linkage Figure 2: Second four bar linkage
Initial prototypes of the mechanism were made of LEGOs, until desired design was achieved.
Figure 3: Joint Assembly
After optimal design was reached, measurements were taken and further prototypes were made with wood, washers, and screws. Links and frames were made by laser cutting 1/4" wood. 5/16" wooden rod and washers were used to create joints between links allowing free rotational movement between joints. Screws were used to place frame on plywood base.