My Own Creation (MOC).
Converts rotary motion to linear motion. Very simple build. Part pricing and other details at [https://rebrickable.com/mocs/MOC-22957/Walt.White/roto-linear/#comments](Rebrickable).
Download LDraw File
[https://rebrickable.com/mocs/MOC-22957/Walt.White/roto-linear/#comments](Animation code) can be downloaded from Rebrickable.
As of summer 2019, I ordered parts to make a dozen of these and gave some to students at a school where I volunteer, and at the Maker Faire in San Mateo, California in May 2019. I will probably give more away at the Bricks By The Bay convention in Santa Clara, California, in July 2019.
I also have a teacher friend who wants to order a class set of 20 of these. As of June 2019, no single BrickLink store has 20 of every part. But the AlphaBrix store had plenty if the color of the 1x4 thin liftarm part 32449 is changed to red.