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=ASIAZI2LB466VALA4BFB%2F20260206%2Fus-west-2%2Fs3%2Faws4_request&X-Amz-Date=20260206T004018Z&X-Amz-Expires=3600&X-Amz-Security-Token=IQoJb3JpZ2luX2VjEG4aCXVzLXdlc3QtMiJGMEQCIENRvZUCi8xSWftvINN2GKxSE7f0gkbRQKc9I7odQvW%2BAiAmy%2FxbnQslp%2Be89oGJ4gCMLJ1%2BZmCMGuVGQGqR240LRir%2FAwg3EAAaDDYzNzQyMzE4MzgwNSIMF9cqpeLXz4D%2BJbAoKtwDQ3YlF%2F16qYaIQ6Kav907kDNMetLJuflNTTLLNOd5UubasetLiCR2UBTsnRoYqPsIyZqDmS0RCPS8qS%2F6RtTWTF7EhEh8TdHkgdQ3ROAp%2BCzGrusdQDSUw5d%2BVvpZR3BUexSriGx5iwjUo6LMloSsptKo11zYL%2BRcIDAsnSaKTN2%2BCuS%2FbN4v2JJIrG774MdrhvSGvENmpx2MsfqJBfxpdtpyaejcumPaSIGJ1509h%2BGWOhs2GjE08osNyCNoCtNTwFsbnj5NgTNtqk9PARkIRo%2BLRzx5abQagNlrd%2FJlsRLXAQHbnpzdvPeCyCYqCQEbwKwBUjkFQvgABZvjeirlabOi5T%2BQhaFyIa3ryKr5NuohyfAQi0KamEwHrT6c2CUva42nj9ONfjr6jwqNz2hMxPMses9oFt4t72QZd%2BjJxkij5vxH%2BGwmdvZHhzv%2Bh79ZVWQd0GSrmmblEnrg9yjD2J8UaWcQ7JrIkzI3j7PwVnECbj5nJ9AWaQecjhXix6RcuPzSwbMAq%2BIbxfElfJzgItCF3a4%2FIIihSAkVAgFPPOhVxnwfh5LgiMxGXIhgZJ9r3S3T%2BrSV72bZUEjfLhWSRvLmC5XFV81VDPUKSaKutzC4%2FcqejgzzLvfS5NQw0q2UzAY6pgGQEPyL1AXQ4zaq8RIvdgiUTeWqNj646Jo5xRJMjZJth51jnBx2T96OMItAe8sCVtcgXpYnurqGTNR0KIv%2BT1%2BOwHqyUqN5uuoDD7cyi9YrhTgzs%2FpzZsGXNirbqom2Bbs6gTJDcL8RkEN2NBEir2fzelayaargaoyoQAITqSPeQIt6tGI3XFY5eJg4jKt16UDysSlqEvCPuOIcNmyYMoBgui4YL2v%2B&X-Amz-Signature=7abfc448c6bfb3d5c772832f9617e094b3ad18ca5bbb7c7640411405fe323478&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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