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Relays activate at startup

Posted: 26 May 2023, 23:18
by RaphV57
Hello,

I'm controlling a fan speed with double relay board and capacitors. When the wemos boot, the two relay are briefly activated. Have a look at my video to better understand.

Is there a way to avoid it?

Schematic

Re: Relays activate at startup

Posted: 26 May 2023, 23:27
by TD-er
See "GPIO Behavior Summary" on this page: https://rabbithole.wwwdotorg.org/2017/0 ... -gpio.html
And the table on this page: https://lastminuteengineers.com/esp8266 ... reference/

Of course this page should be your first reference when picking pins to use :)
https://espeasy.readthedocs.io/en/lates ... on-esp8266

The only ones which are safe to use are GPIO 5 & 4 (D1/D2)
Second best are GPIO 14/12/13 (D5/D6/D7)

Re: Relays activate at startup

Posted: 27 May 2023, 07:22
by RaphV57
Thank you!
I got tricked once again with this GPIO selection... :oops:

Re: Relays activate at startup

Posted: 27 May 2023, 13:17
by TD-er
RaphV57 wrote: 27 May 2023, 07:22 Thank you!
I got tricked once again with this GPIO selection... :oops:
Happens to me all the time, that's why I created that table in the docs :)