ESP8266 Community Forum

- Thu Feb 02, 2017 8:11 pm #61937 Hi Folks,

I have connected relay to GPIO 12 13 and 14 of the esp8266. as soon as connect power to esp8266, it energizes the relay! even before the boot up process or even before executing my codes and functions.
I pull the GPIOs to low when I initialize the GPIOs, so relays turn off as soon as boot process finishes and it execute the actual code. This is not good enough because the relays still turn on and off briefly.
Is there any way that stop exp8266 from pulling high the pins?

- Thu Feb 02, 2017 10:31 pm #61940 Those pins have pullups enabled. You could use a lower value resistance to counter the internal pullups. If you used something like a 330 Ohm resistor from the pin to ground it would probably be enough to keep the relay off.

The other option is to use different IO pins. GPIO4 and GPIO5 don't have pullups. I think 16 might be OK.

- Mon Feb 06, 2017 5:03 pm #62193

Those pins have pullups enabled. You could use a lower value resistance to counter the internal pullups. If you used something like a 330 Ohm resistor from the pin to ground it would probably be enough to keep the relay off.

The other option is to use different IO pins. GPIO4 and GPIO5 don't have pullups. I think 16 might be OK.

I tried adding resistors like 330Ohm and 220Ohm and this solution did not work. I ended up using your second solution of using other IO pins and they are working with no issues. Thank you very much