This Automated Machine Will Braid Strings for You
YouTuber Mr Innovative's device uses an Arduino controller and a stepper motor.
Depending on your experience, braiding thread together can be easy or hard, but either way it's repetitive. Each line must be looped over the other in a set sequence, which is of course an excellent recipe for automation. In the video below, Mr Innovative shows how this can be done by automatically moving three spools in a “mechanically programmed” pattern.
To create the needed motion, the system drives a series of gears on the bottom of the device with a stepper motor. The final two gears in this series move three spools on top of them, which contain yellow, red, and blue string. These spindle assemblies are passed back and forth on an infinity-shaped track via a clever mechanism seen at around 10:00 in the video below. A second servo on top rolls the braided cord onto a “finished” spool, keeping it out of the way and ready for whatever you need a custom multi-colored rope for.
The assembly is controlled by an Arduino Nano, along with a pair of motor drivers. While the electronics are fairly simple, one could see this kind of device augmented with any number of sensors or user inputs to enhance its functionality. Print files for the design are available here.