“Omni-wheels only have traction in the direction of rotation.
This instructable explains how to make an XY plotter from four Omni-wheels, four 28BYJ-48 stepping motors, an Arduino Uno R3 microcontroller, an SG90 servo, and an HC-06 Bluetooth module.
Metal-work is simple … all you need is a screw-driver, three drills, a rat-tail file, and a sharp knife,.
The CNC plotter has an on-board interpreter that recognises the g-code output from “Inkscape”. All that is required is an XON XOFF terminal that can send text-files one line at a time.
The plotter may also be controlled using a cell-phone or tablet as explained in instructable https://www.instructables.com/id/CNC-Graphics-Tab…
Extremely large drawings are possible due to the Bluetooth design. The plotter accuracy is excellent providing the wheels don’t slip! The plotter has a resolution of 22 steps per mm.
The cost to build this plotter is less than $100 USD … the most expensive items being the Omni-wheels and couplings.
The opening photo shows the assembled plotter.”