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=ASIAZI2LB466XLIX3WXV%2F20251029%2Fus-west-2%2Fs3%2Faws4_request&X-Amz-Date=20251029T003022Z&X-Amz-Expires=3600&X-Amz-Security-Token=IQoJb3JpZ2luX2VjEA8aCXVzLXdlc3QtMiJIMEYCIQC%2Fr9r%2F025XSNsjb%2BGOeoakJgwwogH6dKLEAQXxTDvx%2BwIhAKDVbBI1oRnTan7DvPpwWeHI12UIn0WpTVdJMqEAoL3ZKogECMj%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FwEQABoMNjM3NDIzMTgzODA1IgyZ8fG5ZDH3AEgthikq3AM4Wm%2B85mRl%2Fzyf0rXYAHq%2FwanF2NTJVWJJ%2BvLW4qs9iv6Yuem3NFtiFj0TNRcjiRbaBmCrsCIbVwpS9RnQPezOShOdhmgADPLLhLlkHxUGUEbt8LInjKEbgX%2F%2Bk56MNvKbdFKf2HfCPFc80QDSE0MmEbGDKySQKt36BF0Km6TjFgLN2umE2t0XH0a9ijv1bqOidhLnylY9gFOhxL1YWX0BhqMgsbwNXmGnXFxIxRZEH5IP1Fa77jhXMoDNAJlMF8sljBYoAqvKmWtP6BCTn4677UunRaFmkSih%2F1wjYqHhwE6rfaXsjZSDGz%2FS%2FV3EJvkuZUone9h7nMJ9CPqVlbMqhLMdPnn1ECS3Ws%2Flmo8lZEOtL99no9vyLyYUN50YuY07V8QDZ%2BCXAh8xF0JNMR0iy96xIcdOsctP2bYeks0GewUAqEcDHqSNBSitGf7P4J0lpN%2BnYu2bGOcyrdMdj2yhcW%2BnIxj82p312ypFU%2FMhnkjpJJ3WoH6%2FwrcQgG37tj5%2F5R9Ht8csB3LDtcg1XTmJrLtEh%2FxWXqOFkJ57GpnVheXLYLd533g1ARqQY4y41e%2BKTzXORuEUyHnSrAHagsdCzfydSA5zS4MJHGbFq20vd3qTZ61BLViCMf2U8jCFl4XIBjqkAQr83o8QU4JneXIkaNhf6DNbSFj%2Byw26Ih1z%2B81m4tjHkZvZvyNgyxZBtuT8tZ1A71gX3ZtPhOU2T0nvl96xwpMETs%2BGWv5p%2B2EQIzpzjqh38pZs3VplcMrQ8ReTGY7j0gop8g1u2CldhP65tO%2Bw0qCc8lJhGKFSY5Lo2frjGSdUlIHyW8WA%2FAi2jtCfutiEkAd2BDNeh4k%2FoxsK4U2m3nrd%2F38V&X-Amz-Signature=c3b35a719159ced5b42cb9bfc88eced0523337fbb6aa5ded0a587a549688d3c4&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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