I have a ESP-12 with 4 relay outputs (GPIO 3,4,5,15), all outputs with a BSS138 transistor to convert 3,3V to 5,0V to relays.
The software works fine, and boot Ok.
But the problem is with gpio's (all of them) goes HIGH for miliseconds when the ESP boots up. even with 1k a pulldown resistor at every gpio.
How can I fix that problem?? My relays can't click every time I restart the esp..
Circuit: (The switch SW doen't exist, I only draw to simulate the ESP gpio)