Interestingly, I had 2.2k pull-ups on my I2C ports, so I thought I'll just remove them, and use the 4.7k off this board. But, before I put the board in, I tried my circuit again, and the I2C .96" SSD1306 OLED worked just fine without the pull ups. Hard to tell, but I think I see them on its board as well. Plug the ZS-042 into the bread board, OLED still works. I'll try to talk to the DS3231 next. Fun.
Interestingly, I had 2.2k pull-ups on my I2C ports, so I thought I'll just remove them, and use the 4.7k off this board. But, before I put the board in, I tried my circuit again, and the I2C .96" SSD1306 OLED worked just fine without the pull ups. Hard to tell, but I think I see them on its board as well. Plug the ZS-042 into the bread board, OLED still works. I'll try to talk to the DS3231 next. Fun.