https://www.instructables.com/Solid-State-Auto-Reverse-for-Camera-Power-Slide/
Solid-State Auto-Reverse for Camera Slider - Instructables
Solid-State Auto-Reverse for Camera Slider: No Arduino, No Software, No Relay, just a simple low power, four chip, Auto Reverse Circuit!!! Micro-processors and...
for camera slidersolid stateauto reverseinstructables