This horn is SO courteous my car was granted Canadian citizenship yesterday.
Check out Bob’s video:
My buddy Howard does this for a living:
Links to the stuff I used (not sponsored):
Sound board: =oh_aui_search_detailpage?ie=UTF8&psc=1
Buttons: =oh_aui_search_detailpage?ie=UTF8&psc=1
Amp: =oh_aui_search_detailpage?ie=UTF8&psc=1
PA Speaker: =oh_aui_search_detailpage?ie=UTF8&psc=1
12V to 5V: =oh_aui_search_detailpage?ie=UTF8&psc=1
Train Horn (not my exact version but this will work well): =sr_1_4?ie=UTF8&qid=1497644803&sr=8-