VK4GHZ Nextion for K3NG Rotator Controller firmware v 2020-12-17-01 update brings "User Defined Function" buttons for those wanting to experiment with triggering their own custom code.
See http://vk4ghz.com for sample UDF code snippets.
Introduction to the VK4GHZ Universal Rotator Controller board.
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https://www.youtube.com/watch?v=1zuIjArVha8