I once created two tutorials for the Udoo Neo meant for beginners who just bought a Neo and want to connect it to the Internet and want to see their sensor data on the internet. The second tutarial is about controlling the Udoo Neo Arduino in- and ouputs through a local website on your Udoo Neo so you can control it from everywhere in your house and from every connected device (smartphone, laptop, desktop) that has a web browser. As they are setup with Python on the OS side and standard Arduino sketches they are also usable on the Udoo X86 on every OS (Windows, Ubuntu etc). Only the interface device between Udoo OS and Arduino is named different: On Udoo Neo it is /dev/ttyMCC On Udoo X86 usually, you should find the Arduino in the COM3 in Windows 10 and /dev/ttyACM0 in Unix/Linux OS. Have fun! And if you have questions do not hesitate to ask! Here are the links to the forum threads: HOW TO: Make Udoo Neo/X86 an IoT Gateway of Sensors How-To: Control Neo/X86 Arduino from Web page
There is no Python GPIO library for the Udoo X86 yet. You can adapt the NeoGPIO library for the X86, that should not be a hard job of you know Python and GPIO. https://github.com/smerkousdavid/Neo.GPIO