This is not in any way my design or idea. It's based on the work of Daniel Perez over at https://generatorlabs.wixsite.com/spectrum.
I just converted the pdfs of the schematics and made some small improvements for easier connectivity, to allow anyone who want to build it theirself.
I thank him so much for sharing this awesome project along with the arduino code. Please check out his 3 part video...