I have an issue- which I guess is has some power issue. I'm using ESP32 and a 3.3v Dual relay.

My code is simple ( switch up and switch down ), and works fine.

The thing is that when all wires are connected between ESP32 and Relays, and then connecting ESP32 to USB cable from a 2A adapter to main, it just wont start ( I have a MQTT message send on boot ), BUT when I first connect ESP32 to power ( same cable, adapter and so on ), and only then connect VCC and GND to relay - all is working fine ( buttons and MQTT ).

I tried it several times, and it is persistent

  • 2
    I'm voting to close this question as off-topic because 1) without a schematic it is insufficiently documented to be answerable anywhere 2) it sounds suspiciously like a duplicate of your other current question iot.stackexchange.com/questions/3324/… and 3) the question asked is about the circuitry surrounding the ESP32, and not about the usage of the ESP32 for an IoT purpose. Aug 25, 2018 at 22:43
  • It is not the same question, and now I’m trying with esp32 board and it has different behavior. What schematic do you need? It is a 4 pin connection ( vcc gnd in1 in2 )
    – guyd
    Aug 26, 2018 at 3:21
  • You need to show the connections of the relay to the ESP32. And it likely is the same question - the most likely explanation is that your relay input is mis-configuring the ESP32 boot pins. But regardless of that, the question is off topic here as it is not about IoT. Aug 26, 2018 at 3:35


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Browse other questions tagged or ask your own question.