iothing wrote:I use these cheap 4x relay modules off of ebay/aliexpress with the blue songle relays, apparently they have a snubber diode.
Ah. Interesting. Yes I see the diodes. I have a couple of these boards too but haven't tried them yet.
So, when one of these relays turns off, your ESP8266 resets?
The only possibilities I see are:
 - some sort of disruption or impulse on the power to the ESP8266
 - field collapse of the relay causing interference, possibly through the reset
#1 is the most likely culprit I suspect. You can try diagnosing #1 with a scope on the ESP8266's power line, or you can try to reduce possible effects by trying better power supplies, adding more power filtering at the ESP, dedicated 3.3v regulator for the ESP, even trying separate power supplies.
I still have a hard time believing that interference through the reset pin is the issue, but I haven't done any specific tests for this. You can try separating the ESP and relay board by a meter or more, you can even try removing connections between the relays and the ESP, then using an external jumper or switch to energize the relay, to see if the effect is still there. And you can add stronger pullups to reset of course.