Think I first saw this on reddit here. Thought it was a good concept so did some more digging.

Found v1 engineering after like 5 minutes on Google, cool crew pumping out CNC-adjacent open source projects, since dragging a ball across a sand pile is functionally the same thing as CNC/3dp/CoreXY, plus without a z axis they probably had a pretty clear path.

Pretty straight forward setup, 3 rails, 2 of which are being traveled by the 3d printed trucks via toothed belt which is fed through (2) cross corner motors. Middle arm can move up/down, left/right via motors going CW/CCW combinations. Middle arm then has magent which drags metal ball across the sand (baking soda)

Picture of the metal rods I had to cary 3 miles back from home depot because I didn’t have a working car at the time lol

Ball carrying system with ball seen in middle

Pic showing how three arms are mounted to bottom of table

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    ![IMG_521744F3-51DD-4402-953B-BC5EEABEF20B.jpeg](https://prod-files-secure.s3.us-west-2.amazonaws.com/286b54df-77c1-4797-839a-2a9cdff8e527/2c0c97e7-3473-4998-a5c0-752df02b3e3e/IMG_521744F3-51DD-4402-953B-BC5EEABEF20B.jpeg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=ASIAZI2LB466VMOAKZDZ%2F20251029%2Fus-west-2%2Fs3%2Faws4_request&X-Amz-Date=20251029T102022Z&X-Amz-Expires=3600&X-Amz-Security-Token=IQoJb3JpZ2luX2VjEBoaCXVzLXdlc3QtMiJIMEYCIQCTKkD3X3kjtTkhQW%2BOSFob1pgezpyDUNMFZ5h0cAqY7wIhAMg8mWacIqfiCKkTVdTt0D3J%2B75pxiHPzSCpRY3R1%2Be6KogECNP%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FwEQABoMNjM3NDIzMTgzODA1IgzVeY7v4SkoCNSxBL0q3ANwBkcPHN5YSHslhSV6qtOWK4srMkpmbL6QYD22TwDXWm9M7narRFv2aLnicAXk6ig4UabFSe1t2JSESis1rxHjpwHrmShnEW%2FpfOLv6hNxVelT1Uv2a6FzRtulJazRGAjYaHxUzPp5yuU%2B%2FQG%2Fru%2FCAldkhLOvddfUx%2FyYCMV6tANO4Z%2FlYb9r6XL%2F7tbpGFojBPOaO2oNptsNl3fvKcW4ZtlWqMZfwFuCC6L%2BCRTVnw9UFGCyrU2Cd2J6oOjWBuWRtF%2F02ERjolGw%2FfoymZ%2F%2F5feVcotjkCqsjw4z9befi%2BCETIJw3GfFaY0dD9TALNaloVfW7qJ5QDyPtcDvXR67Cnfnn3ICIDoC5G%2F3%2B86ASPM8fSzgVNQtFknIyOfqtU4Z5MluxRY7G4k4LDgFfsAO9VE6qKxFa9yG9Go0WqiZqeh5LP%2Fe%2FYlMjYJexa6sr3woU3fIDdWVMkFw4vBpoyULnYpLbxza3MbZHLDi9h7BY39oiGAuQp%2Bk6Xc%2FFvddlw4a1eQ1hgcnlV7YsKkS30TQVxTG129RYmsJG6%2FNrl2sJRF38prPO%2BKvEg%2Fd85%2FbsXQhk%2FOltd4y0hjh2acWY0ATDZSW%2Fo3AgWwILazV8GJ5MtXPeGXCtXAo89jg4DDvyofIBjqkAcsZpkGHLjXT4%2B9gIsJTczSIraark3Fw8uYVv%2BloVtEN2WN6OitNZbuewbD1q4oPQ2vmI6cu0aAjFruuoFAVUNa49s2sKUbauFuaYei4o1wyvh%2BHPOii2Su4BPHq3%2FJtvrK%2BajCxXzPUHiPKAUzsLYxE9lZzQnxyKnKCL2fzq9Fxedgt2zWv2M350oXQuMAfsuCGRB%2FDAP4niA79PhQ88o5Gm%2BtT&X-Amz-Signature=e6396012723bbff0df7c115e1d141a1081744a675e2d85aa30c0af985f8f6089&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)

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    Final result, pretty neat, currently dissembled sitting in my closet until I find somewhere to live that is > 600 square feet.

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    TMC2209 Pen Laser V2 board with ESP32 on top

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