i have a ralais board with 8 relais as "active low"
From my Lolin Nodemcu V3 i go from GPIOs to an ULN2803 Transistor Array because of 3.3V to 5V converting.
So far all works great.
So if i set GPIO to "High", the ULN2803 sets the input on the raleisboard to "LOW" an the Relais switches ON.
My problem now is, a few relais switching to "LOW" (ON) at bootup of the MCU for a part of a second.
This is happan to all my nodes with relais connected to.
This is not very good for my outdoor fridge for example or a water pump.
i used hardwaresettings for gpio ports like "GPIO Boot = Active LOW.
But it did not change anything.
Is there someting like:
Code: Select all
digitalWrite(gpioX, LOW); // prevents relay from activating after power-on
pinMode(gpioX, OUTPUT);
Thank you for your answeres
Sascha