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=ASIAZI2LB4666G5M345R%2F20251222%2Fus-west-2%2Fs3%2Faws4_request&X-Amz-Date=20251222T042012Z&X-Amz-Expires=3600&X-Amz-Security-Token=IQoJb3JpZ2luX2VjECQaCXVzLXdlc3QtMiJHMEUCICxmf9wjVTKsm2LHqZjUbUBGKC9HDi%2BV%2FO9eDYzY43DBAiEAn6sHcruiPNcWXUQzfZp2KtFqv1ZhO%2FiMKnDu%2BRbLMo4qiAQI7f%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FARAAGgw2Mzc0MjMxODM4MDUiDGHlI5Z9tce%2FyzQHCyrcAwOvlPCCWBUbPaTyWp2YKpS8Kc%2B91bgpX9P2f4d1SGuaREHumqdYw0z9nPjCp6Sql77x1sdBiRCi03qZrlqEtpXaVEINf%2Ftqsetr3JSC5ELnoOQ%2FyAnkxR3elIENk8Qo7XA6zPqN%2F%2B%2BTE6yN7XTTivg2dQiJMyigWWt5drRbr13I01pgLe0m5GZeoNmJxDeEyxbYPXx5HyTjNJuBZJVfoSwXsiaqTj8ZBsPNmgPYnkEUajj7%2FHW97rDcA4eb%2FZvjltfb%2FO7360CXed%2FhH02UhRYds1Bdob%2F3vCpjUnMexcZb4ckJtL8Z6XCm%2FoF27ubzp7YsWEGyWDQ%2B9Ra1QC6RC97%2FqpnU6YodfaAveia%2FGdoSpw0Gxc3ak87oa9Hs3Gl5Tlp2LR2AQLXhWwP%2FnSdvDIyitx5cAvBzvslPGNHiB0dv7%2Fh3dn8Ra9xEByOBJIeTsxFeb53psJ6VXDQd1IACj510re4IfGzaIKHfxxyo6BHm6PuB7l3f%2BW10R25TZNu0m3LDEsUydX%2BS2rvi9g6%2FuE67JAZVYJUzigiOeuWJUeQxnlLhAc07sk7Uo5Et2m82Kz92HjWjPCW4qr7aOo%2F8rRrBWEZ6FG%2Fv2vwtt6AJI21w05GmjTuI%2FyXxUgNYMPqFo8oGOqUBXJJ%2BEHhiYHE%2FdbWlhlOAkRbZRDoareIJm3QW8P%2BFwRC9gSvXC46O500rSzXc5x5CYqKeSotmRqJWReus4c8%2Bgmlbj3skNTRsQy9cpLVppt8y0SM3sLHCSLzyh2DywGL%2BFsEfomxghFmkUH8mVbCJKk%2FlciCfYV5rG1GVIPf3Brq%2FkShURlcKpo3AD5Wv%2BJL3niR4uEnSzt0LZ46GeOoGQOsCS9EX&X-Amz-Signature=e357fc35c16ac98911a94d9ce3384ae0964f5fc7a43ce67a8968383b5b5e5866&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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