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edited Aug 10, 2018 at 1:42

I've connected the MCU to a cheap chinese 24/12v to 5v car phone charger and hooked some wires to a relay.When I try to program doesn't matter if the pin is set to high or low , as soon as I touch the "IN" wire from the relay into any of the selected pins, itthe relay auto actives.

here is the schematic The charger input is hooked to a 12V drill battery for tests and the output to arduino is an usb port that I soldered wires to it's respective poles.

USB from Chinese charger Positive pole ------- NodeMcu Vin
USB from Chinese charger Negative pole ------- NodeMcu GND
USB from Chinese charger Positive pole ------- Relay   VCC
Relay Ground --------------------------------- NodeMcu Gnd
Relay DataPin -------------------------------- NodeMcu D0 or D1

And here's the code:

int port = D0;
int portB = D1;

void setup() {
Serial.begin(115200);
pinMode(port,OUTPUT);
pinMode(portB,OUTPUT);

digitalWrite(port,HIGH);
digitalWrite(portB,LOW);

}


void loop() {

}

But the result is that the relay will always be on activated ( IN pin = Low ) even connected to D0 that is high... Any ideas ?

here is the schematic The charger input is hooked to a 12V drill battery for tests and the output to arduino is an usb port that I soldered wires to it's respective poles.

USB from Chinese charger Positive pole ------- NodeMcu Vin
USB from Chinese charger Negative pole ------- NodeMcu GND
USB from Chinese charger Positive pole ------- Relay   VCC
Relay Ground --------------------------------- NodeMcu Gnd
Relay DataPin -------------------------------- NodeMcu D0 or D1

And here's the code:

int port = D0;
int portB = D1;

void setup() {
Serial.begin(115200);
pinMode(port,OUTPUT);
pinMode(portB,OUTPUT);

digitalWrite(port,HIGH);
digitalWrite(portB,LOW);

}


void loop() {

}

But the result is that the relay will always be on activated ( IN pin = Low ) even connected to D0 that is high... Any ideas ?

here is the schematic The charger input is hooked to a 12V drill battery for tests and the output to arduino is an usb port that I soldered wires to it's respective poles.

USB from Chinese charger Positive pole ------- NodeMcu Vin
USB from Chinese charger Negative pole ------- NodeMcu GND
USB from Chinese charger Positive pole ------- Relay   VCC
Relay Ground --------------------------------- NodeMcu Gnd
Relay DataPin -------------------------------- NodeMcu D0 or D1

And here's the code:

int port = D0;
int portB = D1;

void setup() {
Serial.begin(115200);
pinMode(port,OUTPUT);
pinMode(portB,OUTPUT);

digitalWrite(port,HIGH);
digitalWrite(portB,LOW);

}


void loop() {

}

But the result is that the relay will always be on activated ( IN pin = Low ) even connected to D0 that is high... Any ideas ?

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asked Aug 10, 2018 at 1:30

Lucas Medeiros

Problems with NodeMCU and Relay

here is the schematic The charger input is hooked to a 12V drill battery for tests and the output to arduino is an usb port that I soldered wires to it's respective poles.

USB from Chinese charger Positive pole ------- NodeMcu Vin
USB from Chinese charger Negative pole ------- NodeMcu GND
USB from Chinese charger Positive pole ------- Relay   VCC
Relay Ground --------------------------------- NodeMcu Gnd
Relay DataPin -------------------------------- NodeMcu D0 or D1

And here's the code:

int port = D0;
int portB = D1;

void setup() {
Serial.begin(115200);
pinMode(port,OUTPUT);
pinMode(portB,OUTPUT);

digitalWrite(port,HIGH);
digitalWrite(portB,LOW);

}


void loop() {

}

But the result is that the relay will always be on activated ( IN pin = Low ) even connected to D0 that is high... Any ideas ?

nodemcu relay