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Electronics => Repair => Topic started by: nardev on February 23, 2018, 05:22:16 pm

Title: Relay buzzing unless hooked after ESP8266 boots up.
Post by: nardev on February 23, 2018, 05:22:16 pm
I believe that it would be proper way to put the whole project description but i hope it might be enough for someone with experience.

So, very simple thing.

I power up ESP8266, it boots, everything works fine.

I hook one of those cheap songle relay module boards (i tried other relays too, same thing) and controlling the relay works perfectly. No issues there.

However, if i leave it like that and restart EPS (power down/up), the esp never boots up, and there is silent buzzing from the relay.

Probably this might be all you need:

Between the ESP IO pin and relay board i have 1K resistor, 2n3904 NPN transistor and it switches 5V relay powered from external 5V.


Any clues?

Title: Re: Relay buzzing unless hooked after ESP8266 boots up.
Post by: nardev on February 23, 2018, 05:25:43 pm
I believe that it would be proper way to put the whole project description but i hope it might be enough for someone with experience.

So, very simple thing.

I power up ESP8266, it boots, everything works fine.

I hook one of those cheap songle relay module boards (i tried other relays too, same thing) and controlling the relay works perfectly. No issues there.

However, if i leave it like that and restart EPS (power down/up), the esp never boots up, and there is silent buzzing from the relay.

Probably this might be all you need:

Between the ESP IO pin and relay board i have 1K resistor, 2n3904 NPN transistor and it switches 5V relay powered from external 5V.


Any clues?

 |O |O |O |O |O |O |O

Just as i wrote this, i realized.. why the hell do i have only 1K there :) lol.. doesn't buzz any more...
Title: Re: Relay buzzing unless hooked after ESP8266 boots up.
Post by: ArthurDent on February 23, 2018, 05:58:33 pm
See you got it working. Maybe you have already seen this but there is good information here for future reference.

https://www.forward.com.au/pfod/HomeAutomation/OnOffAddRelay/index.html#single5V (https://www.forward.com.au/pfod/HomeAutomation/OnOffAddRelay/index.html#single5V)
Title: Re: Relay buzzing unless hooked after ESP8266 boots up.
Post by: nardev on February 28, 2018, 05:58:11 pm
THnx

p.s. one of the issues was that MCU had pull-up on the pins i used my default.. so.. it even made more confusions..