Casper Electronics
The website got hacked in 2017 and rebuilt from scratch, but old versions containing the diy-related stuff have been archived and can be found in the wayback machine.
Bookmarks with tag “website”:
Ciat Lonbarde
Well-known name in the diy synthesizer community.
Has made some changes to the page over time. You might stumble upon dead links from forums. If that happens, try adding an additional ciat-lonbarde after the domain name, e.g. where https://www.ciat-lonbarde.net/paper/man/index.html returns a 404, https://www.ciat-lonbarde.net/ciat-lonbarde/paper/man/index.html will work.
Peter B: Just B
Peter Blasser’s blog, which is still active as of today.
Schweizerische Gesellschaft für Mechatronische Kunst
Swiss group of people focused on diy electronics, workshops and events.
WarrantyVoid (Weltenschule TableHooters)
A pretty old website with a collection of all kinds of information on thoroughly inspected toy keyboards and often times their modifications.