ESP8266 Community Forum

- Sun Aug 12, 2018 5:29 am #77699 I have this unit : https://www.aliexpress.com/item/ESP8266 ... 61942.html

The problem is that at boot the relay turns on then off then on again causing any connected devices to flicker.

The relay control pin is connected to GPIO0 which is needed for boot and so the initial state during boot time is unknown.

I set the GPIO0 as output and wrote 1 to the pin at the beginning of the setup().

Also according to this schematic https://github.com/IOT-MCU/ESP-01S-Rela ... 20v4.0.pdf, GPI0 is connected to a pullup resistor

Any help would be much appreciated.

- Thu Aug 23, 2018 3:32 am #77878 any help ?

- Thu Aug 23, 2018 4:55 am #77879 as you correctly stated, the pin needs to be pulled up for correct boot, so it IS defined at boot time.
unfortunately it is not defined during reset ...
there are lots of posts to this topic that you would find using "esp01 relay" or "esp-01 relay" in boardsearch ...

- Thu Aug 23, 2018 12:04 pm #77885

as you correctly stated, the pin needs to be pulled up for correct boot, so it IS defined at boot time.
unfortunately it is not defined during reset ...
there are lots of posts to this topic that you would find using "esp01 relay" or "esp-01 relay" in boardsearch ...

I tried searching quite a lot before posting and could not find any solution to that flickering behavior. I even changed the firmware (this one:https://github.com/IOT-MCU/ESP-01S-Relay-v4.0), but nothing changed.

Is there a trick that could be done to postpone the flickering effect on the AC current till ESP01 boots ?