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=ASIAZI2LB46657MK5FHB%2F20260206%2Fus-west-2%2Fs3%2Faws4_request&X-Amz-Date=20260206T023014Z&X-Amz-Expires=3600&X-Amz-Security-Token=IQoJb3JpZ2luX2VjEHMaCXVzLXdlc3QtMiJHMEUCIQCi2cZn19phzHLb6ZmjYBfhLCigRpXeaiavfxTLHuKKeAIgENRcxgKAyfO408x8TbFy9HeZlxz012MrV1fb3VdoD0Iq%2FwMIPBAAGgw2Mzc0MjMxODM4MDUiDNCI%2FQBnHKoBVLtmRyrcA%2BfRtWNnFqK0X%2BLpyJnGxPJZhMiiScGsNKJVTxvHEF73pKwK%2FnXmB2BmYUCWOa1nzO2lnM8LVpqxoQkHG81vjEkhs%2FUAN3NLtoAc%2F2ErMlJ16D0tPwEp69%2FTdP%2F13FF8Bm6f7ZU%2BZqt%2FUCDE%2FRaFiES%2Bta5h2HOxjBOOn6yv9sJINIXNT1Iqn4BE61JSqRUVKN%2BIoqyoJVVteuEz%2BpIeLtb2SPvTCCygeVFrdDsgswszfIyMpnEHVdPBGjIdZnt884DAY6i2NmIF9oCPxFE08uB0xcufB4pbO7hzhVFbH1i9h21kf%2BQiXpN58P7J%2FwqJU3tN%2FwMfcCXVBT9iAn3W%2FsFB8bXgS25edlt8K6VblG79D2TwfEroUwf4nldx02rX9fpsZZYi9IxVz4zMP%2F6yLlqmxclgDv7xrLWDtPPRyHw4driymwR8fYzv88kDPD7zODGth23Z80enmVO%2FZ3D5vgTAzWkiDctmnTCihvHECERvHZQQnuiZJLr5Lhv0pptnMQi%2BWuDvtkZJDn5HuPvL%2FUpsnTZtIJQpTBB6j6cRgZVMWKGZJlUI5B%2BSbPWdKLs2BAxRTrpkpmssW1OhSIuto1CL9Hyyx57%2FFKUwqNsW3%2FAE0e9FCoVPZVytgYuxMJGjlcwGOqUB2avULQj7qLcvV4e9XbrkUjwnyL3iiltFpL6FVy7KUWyffvNnkjVzewnQefnqHQyp0xLn5DwERhiiOSGPmf0%2FQGKIX0wlW8h8P2QDc5oQDdF1t6CL93y33KT2DHzrIpFFNE0GIrbJCUpDKCIbFXjx9%2Beq2746XvUDpPyfAT9vHpWatTrw5xFbdXzL5ug4HljCSizv4fuKOJJQF3qQaoOArsPIuFXe&X-Amz-Signature=2cad5986c63b0b13b1b8236394d4177db117d9c18fcb2a8b89dfc5d001fa1bb7&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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