I’m trying to do the same project. Do you mind sharing how you wired your pi to 8 channel relay. I have seen may diagrams and none of them work for me. I was doing a direct connection from by to relay. I think I have to use an external power for the relay since my pi is not strong enough to power my relay. Because the relay would just flutter while booting. I’ll tackle the software side later on I just need to get my relay working properly