“An “Omni-wheel” only has traction in the direction of rotation.
This instructable explains how to make an XY plotter from three Omni-wheels, three NEMA 17 stepping motors, an Arduino Uno R3 microcontroller, an SG90 servo, and an HC-06 bluetooth module.
The plotter is a three-wheel version of the four-wheel plotter described in my instructable https://www.instructables.com/id/Omni-Wheel-CNC-P…
The metal-work in this new design is much simpler and has been kept to a minimum … all you need is a screw-driver, two drills, a rat-tail file, and a sharp knife.
The 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 my instructable https://www.instructables.com/id/CNC-Graphics-Tab…
Extremely large drawings are possible due to the bluetooth design. The horizontal resolution is 8.78 steps per mm. The accuracy is excellent providing the omni-wheel rollers move freely and the motors resist each others push!
The estimated cost to build this plotter is less than $100 USD … the most expensive items being the omni-wheels, motors, and couplings.”