ESP32 power led start blinking at 2.2v at input Pin when 220V AC bulb on

[mm_ashraf]

I have circuit connectivity for 220v status check. 220v is connected to relay module Com Pin. then this 220v is applied to power supply module AC pins, now this power supply convert 220v to 3.3v. I have connected 3.3v supply pin to ESP32 Pin25. This pin will show power level high when there is bulb or fan ON via relay module and visa versa. All system is working ok when ESP32 is power on from USB cable. When ESP32 is power off and some one ON the button of 220v bulb/fan, There is voltage level of 2.2-2.5 volts is coming on Pin 25 when I check the multi meter. and ESP32 remain off but power LED of relay module is becoming ON and ESP32 is also blinking, I also check that power levels on 3.3v ESP pin is also high or 2.2v. I have unable to identify the issue , I have changed ESP32 Pin 25 to 26 and also change power supply module . but still this strange behavior is happening with ESP32. if I disconnect pin25 from ESP , all become Normal. it means that there is issue with ESP32, as 2.2v is at pin 25 is main cause of problem. this Pin25 is input mode and I can not avoid as in normal I have to decide light status at remote side with this input. only my issue is that 25/26 PIN input voltage is creating problem in ESP32 it self.
please advise so I can get out of this issue

[mikemoy]

Can you provide a schematic of all your connections. Or at least a drawing. There is probably something back feeding power somewhere.

[mm_ashraf]

I have attached, diagram and code as well for further analysis and support. I will appropriate your support in this regards

[lucx325]

the 3.3v pin can also be used as power input, so you should check， when the bulb is on, the voltage on the ve+ of the relay.， why do you use the NC(normal close) port ?

[mm_ashraf]

I have used NC(normal close) port as other side of relay is connected with two-way switch. if also usefull in case of failure of ESP32 module. When bulb is on, voltage is coming via power supply module pin in ESP32 module after disconnecting power supply there is no voltage on +ve of relay module.

[lbdroidman]

According to your schematic, I'm kind of surprised that you didn't set something on fire or electrocute yourself.

ARE YOU ABSOLUTELY CERTAIN THAT YOU ARE QUALIFIED TO BE PLAYING WITH A/C POWER? I would STRONGLY advise you to seek qualified assistance.

Regarding your circuit;

So there are a few things wrong.

1) The "-AC" inputs on the hi-link power supplies needs to be connected to AC NEUTRAL, otherwise (a) you aren't actually powering them, and (b), you are actually driving AC LIVE into your "-ve", which is dangerous.

2) You aren't actually powering the board. You need to take the "+V" output from one of those power supplies and connect it to the "3V" input to the dev board and relay module.

3) If you activate the relay that says "2", the whole thing will shut off.

4) Your photograph shows a 2-relay module, yet your schematic shows a 3-relay module???

5) Can't tell why you have 3 power supplies attached when two of them are connected to relays that aren't connected to ANYTHING.


Although your description is pretty unclear, I think that what you really WANT to do, is to have one of those power supplies set up to actually POWER everything, and that you are using the other two just to tell the MCU that the associated relay is in the ON position. I also think that your "2-Way Switch AC 220" really should be an SPST switch, just to switch mains on and off manually.

So re-wire like this;

L220 --> switch
switch --> COM of all RELAYS + "+AC" of power supply 1.
"+V" of power supply 1 --> "3V" of dev board + "+ve" of relay board
"-V" of all power supplies combined --> GND of dev board + "-ve" of relay board (AND NOWHERE ELSE!!!).
N220 --> bulb + "-AC" of all power supplies.
NO of relay 1 --> "+AC" of power supply 2 + bulb
NO of relay 2 --> "+AC" of power supply 3
"+V" of power supply 2 --> D32
"+V" of power supply 3 --> D26.
D21 --> CH-1
D19 --> CH-2



HOWEVER, unless you really need to know if the relays are BROKEN, then I would just leave out power supply 2 and 3 and all associated wiring, and understand that the relay is on or off based on whether you are driving D19 and D21 high or low.

And as an alternative to the second and third power supply, if you really insist on having an input from them, might I suggest that instead of using power supplies to create a 3.3v output, that instead you just use relays with 220V coils to pull gpio pins low? It works like this;

AC N/L: relay coil.
D32: relay switch NO
GND: relay switch COM

Set D32 to input-pull-up and either poll its state, or better, tie it to an ISR. When D32 is LOW, it means there is power coming out of that relay.