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=ASIAZI2LB4662ZO2WPA2%2F20260323%2Fus-west-2%2Fs3%2Faws4_request&X-Amz-Date=20260323T224015Z&X-Amz-Expires=3600&X-Amz-Security-Token=IQoJb3JpZ2luX2VjEL7%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FwEaCXVzLXdlc3QtMiJHMEUCIQDXwk1rNLWPeerG4plSV8GZQTg3UCjTOqY40KG2J9r0MwIgCccCkezVtxD0NmIyMkp3YRxv7ns0Q2QH4KopqsD5TRIqiAQIh%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FARAAGgw2Mzc0MjMxODM4MDUiDHk9lO19MfY3eStY5SrcA4l7xWzZSZCzvIje6nhSXf5g4P1My9YtbdsqJkEZcQwADNOfB3TgVNXzlBHzIU%2B9mZjT81ODy8zcfQv%2BwxJ%2FxSPEupY2V8b%2FyzW28godDNVPW%2B429sUhRIw4T4os2Q%2F40GJFsM1mNOIqdAvCyyzPMGlg%2BZKFavajTTpC7KYXsJPUeoKZ5dRUtLma0OawwMIakqLakH1W9oOK4gjXBghg0Bp7sGXTpjaXFsVdsxkuTwM7Y0WkxhnXcXl4GCpgfK2cXD7uMCBX70zass2AAPFUKtt%2FEO0Cex%2FmkPGmWoONvDYYcP7%2F9S0iFwqdgeYD1yaGBMPzxsClm7Y0K5oz7VRZWIiUBfvbCJc5ho01ICzPnljYn3RrzaRlSuBkFquhGpkwcoYYIREqAU07IkEM03%2F%2ByJLHDPe8VoWH8JHYuqWFNvacF51eMMZ8bMQskXSe%2FwSzFQoXj6uisG%2B1dToQ73%2FNlhTWcTbhCZIdTyxOO%2FK24mxmb9HXQGSf4nu9P%2FA7EilkTbbtOP6ZFKc89cRv8KJR3KyWTK0st568Z2RFag7JY%2Fx4z3TCj0FROzL55r9TzktnnY7E%2BI8p8hCcV19XX5dko6FcHFwIWv%2FxNv7Uf6XQ0ypXPbpSdxmN3QkcBGdEMJHehs4GOqUB2VwQZfIgDUJzNtpYcfUgG8n%2BQjDr6bOVQtfTeXiLuUnvtwQ%2BOCGhG9J997w7uFr10fdAzWiTUmINNOvMYYDf0nDI%2FpKPkUTu8Br2DlhA0Lg8csQL2f077fKtqNx2LRi0fwOrA%2FZ3c0cymvEp42wanCRX0Es6mDmoM1iaOMeeKWDluU%2B0Y7M9FIGAtex9q30Q7%2FuQ5cp5IDFg0oy%2BCVeo9P0W4dod&X-Amz-Signature=ebeb3641469fbe39354e7570d5285e2b879d1ede2bd4eaddcfe090b080bc2f3f&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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