Linear actuators are motors that work in a straight line. They’re very useful for controlling valves and levers, building robots, and retrofitting old mechanisms for digital control. The simplest form of linear actuator has only 2 positions, while more complicated actuators can be positioned just like stepper motors and servos.
I needed 32 linear actuators for my latest project, and I was shocked to discover how much they would cost. After a little thought, I decided that I only needed simple on/off actuators, and I would try to make them myself using off-the-shelf parts.