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=ASIAZI2LB466QJH5RXYZ%2F20251222%2Fus-west-2%2Fs3%2Faws4_request&X-Amz-Date=20251222T023017Z&X-Amz-Expires=3600&X-Amz-Security-Token=IQoJb3JpZ2luX2VjECIaCXVzLXdlc3QtMiJHMEUCIQDKhh98CY4S%2BtfRdHIc8PaGWZhKJM3sJRVn%2BEmkhkXJUAIgI%2FkkbvTv5XFK07XE%2B9%2FmmPeIWeJ6eT2iPMbtv5jjc%2FQqiAQI6%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FARAAGgw2Mzc0MjMxODM4MDUiDCVw4mYHc5EyB1J6eyrcA3utZ9TSNDyw%2F5zrRiSVb5kEB2wGuMp4QIxqHlom%2BCzz3edzvz3nXhOdIf3ZbuEF84LgK%2FsNJtNXsbrO2wt5RKT%2B42c%2BdMSABnVN5aVULWOlgLSMLvJiDTADypFhuAAXVIGeyH3YWxU2jeQuugnaH2S4KaRA9UkH9h%2B8wjrdWPplDSjUvzKA4nv8Y3Gm9EjV2oJgTmY43PABW6PMZWoTFxLVQTuSnLynsWiipbQ576uGsHGqSbcqmNK7Pm4m5eCoAsApPB4nhUbpJKVg5S0t1kF9bf33LLXn1PcPmIG45pk%2FrRTHC7nn24n11f5QqTdvEUfmKkaVK4fsqYzY9thTKaITvhy55C%2FX7qWqDNeKADtHQhQrh%2BkybV5qzzPLJc3CKzOQWsee4EUaLaiA9YiSYPhkBg%2BgLh%2BsjMlaeka2OBMV6RIU9a3uWKZpkcV8O7optq90yYFguf%2BLw3fVCuwz79lgiqbouosbRfeVLoi7pQleQE6FtBCFx7TET1JE0eVKTvsQJAk8mmhND6vQkh8mxoNt%2BPR0Cpxrluy9eGjdOOOmsv9p%2BF%2FW4epQdQckfbZ7NfD1%2BqL3OXRd%2FZzC3wv63u9O%2FnHt%2FiWWlWd9NmDgQjjqk3QMzFyqdbwaApE7MP3RosoGOqUBowf0siKDFEc7zTc5qMcplIDbLgQ8PGz2uP5cH0Cz%2BEbQ7nSz9Y%2BO707AOT1WNk6AgCy0%2BW17NUbCeYTmA7%2BnyyEQXjoR%2FQKjL2obLVoAL2WTr49%2BaxLsjkWBWb%2BYrcmyIMrPd4xQ5FjA1lDtdylld7JsJfbMQ18Vk0eSrXcwqbG72JK7tNpcCx9LfmOce1JZ6dPdZ2LAHYpApdUhgB%2Bf5G%2BB2Ql4&X-Amz-Signature=8393e11d81ec1833d323d68449461313f355995a76acecaa567089918336527f&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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