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=ASIAZI2LB4664IQKDUTA%2F20260323%2Fus-west-2%2Fs3%2Faws4_request&X-Amz-Date=20260323T213035Z&X-Amz-Expires=3600&X-Amz-Security-Token=IQoJb3JpZ2luX2VjEL7%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FwEaCXVzLXdlc3QtMiJGMEQCIGsPc%2BVDIobwrwa%2BP2EXps0tW4JmWSknqAdvxeWsdOyCAiBOuEE34boxQ0oOIdYgvexPKfFkvffVMWRaLPy9OYwylyqIBAiG%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F8BEAAaDDYzNzQyMzE4MzgwNSIMhj9HzfpMhxhQhvzCKtwDcrnhFX%2BOvx%2B9xPhVgJEbghf8%2BaT2YpDVcAL9X%2FETBNOQLxetPoDa%2FVucUmWT%2FVhPB2Opzrc5Cq%2ByUcM3wtihpV5tt8J8%2B9ZpvEYW30vZnPin6POmkmxSx143WAL4%2Ff7tKh6l9I%2B9rMh7smSs3p5WkvJp7iZjItUjzPxYuPePY%2BkronW8%2Fhh0YalmbUKxSgz2tiCRwVvnk2zYXPUxosFadAgGawV1fzZOKV20zWyhuIo0zo%2FK41ni5QWWnKzgWoQ5NB6ONR3iZD7G3np7nlSuy%2BfzfGk25dqfi0HbTy%2FO7gOyozWQnIQZqGrHNioM48FVht1OF5cemVOivosqEm8Y7AKEfuwzpvOBzzZfUYMISfLkvwS8CB7139z3iTyZFtl%2B7raC7o06WFkKUJ82j0lZXBDJmlTv9HaO9kdqVKKddf%2BruxwYM9m0bWpL39Ujure3Z%2BtywSy8r8fB%2F0%2BdjGifN2XA%2BMhyeIsnYAhK57UPrOvTNxqADmRTO%2BgQbwzKCQ3R7G5v3gXEFIsCR%2FGMuv4%2FV%2F%2B4OQIV6G5bihsQcbxCCX5GQDUHlLTqDm%2BI7qYxLTbFym9G5wsh3aXxzMnv9hG6en%2BCaM%2F3UuTitmk49OVtHZKIqAU3Bz%2BoJT66%2B80w596GzgY6pgFPjdZMqk9FLb1D8gXen2CC3zJDKosAkdmvTz1Zm8O7rcg7jnSC18BvaZr57x0XcJEEsvxZBX3eyLXM4qLEJYc90j189RCkedPB0gyXf5U1eZbHW4Of%2BCRfvto%2BnvW%2Bn6pXTg%2B3mCLYrPcEtPDzg%2BUBqRdl2HbEd23Wt55lAtWQKMcZspuJFobq9UvEvZi68FSo73oH%2F3vUFHKUd27vn3IiTGuJeFQ2&X-Amz-Signature=469e96ec2713ad0733615133450ebaae2c010cb7be2b06c5a57109c90a0b6d9e&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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