As much as some of us don’t like it, building things for real requires some mechanical component. Maybe it is something as simple as an enclosure or even feet for a PCB, but unless you only write software or play with simulators, you’ll eventually have to build something. It is a slippery slope between drilling holes for a front panel and attempting to build things that move. Sometimes that’s as simple as a hinge and a spring, or maybe it is a full-blown robot articulated arm. That’s why [RectorSquid] built Linkage, a “program that lets you design and edit a two-dimensional mechanism and then simulate the movement of that mechanism” (that quote is from the documentation.
The program has had a few versions and is currently up past 3.15. To get an idea of the program’s capabilities, the first video below shows an older version simulating a ball lift. The second video shows the actual mechanism built from the design. The associated YouTube channel has more recent videos, too, showing a variety of simulations.
The software is for Windows and there is a different version to use if you still run Windows XP. The documentation says that it appears to run under Wine as well if you prefer to run it under Linux.
This isn’t going to replace a high-end CAD program’s analysis features. But the price is right and it looks straightforward to learn. If simulation saves you one false start on a project, it is worth more than the free price.