videos

https://www.youtube.com/watch?v=th9v66KzUCI&feature=youtu.be
https://www.youtube.com/watch?v=nSWsuVO5O_Q
https://www.youtube.com/watch?v=hSZ8BhqtTVA
https://www.youtube.com/watch?v=BdZcVEC8SZU

various approaches

http://electro-music.com/forum/post-382662.html
https://mitxela.com/projects/ribbon_controller
http://electro-music.com/forum/viewtopic.php?t=61389
http://modularsynthesis.com/cvs/cvs3.htm

parts

https://fr.aliexpress.com/item/for-ps3-SA1Q160A-Controller-Circuit-Board-PCB-Ribbon-controller-conductive-film-5pcs-lot/32815650731.html?spm=a2g0w.10010108.1000016.1.7c2d06a0SdsMP3&isOrigTitle=true