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=ASIAZI2LB4664V3IR4JA%2F20260206%2Fus-west-2%2Fs3%2Faws4_request&X-Amz-Date=20260206T022021Z&X-Amz-Expires=3600&X-Amz-Security-Token=IQoJb3JpZ2luX2VjEG4aCXVzLXdlc3QtMiJIMEYCIQCGlMiJs%2FUxhTuEAZDeL8Vt2x3u%2Fo6JpqPDcZNlG8PqJgIhAP0tpMInbA66ty625JFtwBI96mMgWv60FkdvYVzeJsySKv8DCDcQABoMNjM3NDIzMTgzODA1Igx68at2p15dMZSrkSgq3AMu2BwwTNlEChCDm4N5ITE2t3WXU5xEEYvQLEBwDUb1y6DBAdXYk4HYGerkvAUVE0nnfyiGBHVjxGlfUIwUj9rys4cc6NcpLVRHjz%2BxVMaSj%2Fj7t0Zk3wjzl9fwzIooKlgQU3uH%2F22bHcHndLglRpPdcAFP72XPv32qD9eXObFKKLWmXpMQ6QC%2FttX60MH8DdiBUbupBV4c%2FS7raPIJFKnA724Huq3vQGzOENA5Go%2FY3G%2F1sjDvZvSPVP3U868fhGJoV5mday0IyShPCp8XdZE5nVZ8w3gWIRZ7H5pA9BXwKy%2BsdmBrwzMGAq25sI6sjlh9c5Biw1FULJCgGL53Cd46WxY0bwIP60oRQBOFMgmVlYBiNiB1qiPL4mUfINSjoaUoiG7RVWi%2BMfKUSCa9BiinRRDdIVwgb02f5BVTbEPUW0xA%2BoEKj3ezmq0NwQ2grm83FxsBytPzZwy9a5eG05%2BCMpYbrCZINF0EP5k4Id214LPSMMpOR7DzFHEJEFP2mRasgHMf%2FMyn%2BriftuRAvXpMwOgWBtHcdNTf2Jta7xXAI8%2BnkEzgQnJpn8AppeAyv1vc%2F5JE9KBOPusrx%2FQ%2FuhzF8V%2B%2B6L8ZiiD5d3c7%2BAwUqFXpcSwvtoTZyoEh5TC0rZTMBjqkATcX3IK1seHIQxpX5f9McI7QC76sDzWaTsS1k4EU8CuIBIzzdNDQl0%2FW%2Bp9ieyNBQ5YrO1Ilfn5I2Y8urMcnsn4%2Fs8cM2glJEoq8SpYPWtrICbhMeMfCuPnhXl5e6J2Ko87OQ6AGfirGt2iMzRH32w4xT98hK75HN1Nd5dawkzaZ4l82Kac64OmY7EzvYGRGEu39FGzX06%2FuhiVDGZoAXkrQOkT%2F&X-Amz-Signature=88b9d74194187eac7243d800e377258f2edd715bad849d35e4f1c5757bfad79d&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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