Hi Angelo,
Appologies for the earlier off-topic post.
I'm using spare parts to set up a system. RPi Zero W, 4 channel 5V Relay with opto isolators.
Picture below of hook up. I've edited Pin assignment in HardwareSetting table (pic below) for both GPIO # and board pin #, eg GPIO4 = Pin16. 5V power Pin2 and GND Pin4.
POST EDIT: The Pinout Chart below is INCORRECT. If you happen to stumble on this post looking for a pinout solution for your RPi, this one is not the droid you're looking for! (I'm leaving it here rather than delete the image so that people can see what they should NOT be going by.)
Attempting to operate IN1 with GPIO4/Pin16 without success. Recommendations appreciated. The screenshot above says Pin4, I've tried with both 4 and 16 in the field.
TIA
I've been doing a bit of research and it seems that there are some dev components missing in the debian and armbian images for opi, that are obviously included in raspbian.I'll have a look at it when I get some time, but right now the priority is to get the watering system working.
Will.