The schematic diagram below is the simplest way of connecting a DC motor to NodeMCU. It is not possible to connect or drive directly the motor using the NodeMCU due to several reasons. Although some DC motors work even below 3.3 Volts, the variable current and the noise involve when driving a motor may damage the NodeMCU.

Also, since we want to operate the motor with reverse and forward motion or CW / CCW, it is not possible using only the ULN2803 driver IC. Thus, we need to use two relays or a motor driver IC to enable such functionality.

In the diagram, the motor supply terminals are either connected to POSITIVE  or GROUND polarity of the supply line depending on whether the relays are active or not. Two signals from NodeMCU are needed to achieve the needed function of the motor.

The program below can easily be modified to change the direction and the speed of the motor by just changing the state of GPIO and the delay value. 

 DIAGRAM

PHOTO-SHOT

 VIDEOS

1. Full Speed - CW / CCW

2. Speed 1 - CCW

3. Speed 2 - CCW

4. Speed 3 - CCW

5. Speed 4 - CCW

PROGRAM

/*  Experiment No.10

  By: Rolando Estomaguio

        Radar Specialist - Electronics Engineer

        http://www.kits-gadgets.com
 

        Objective: To learn the operation of NodeMCU and utilize its full functionality.  

        Title:  Motor Drive Interface   

        Description:  Drives the motor forward and reverse using two GPIOs. 

*/

// Using GPIO5 and GPIO4 to drive the motor through ULN2803 

void setup() {

    // initialize digital pin 5 and 4 as an output.  

pinMode(05, OUTPUT); 

pinMode(04, OUTPUT);   

}

// the loop function runs over and over again forever

void loop() {

   digitalWrite(05,HIGH);   // connect the motor positive terminal to B+

   digitalWrite(04,LOW);   // connect the motor negative teminal to GROUND 

   delay(2000);   // wait for two seconds

   digitalWrite(05,LOW);   // connect the motor positive terminal to GROUND

   digitalWrite(04,HIGH);   // connect the motor negative terminal to B+ 

   delay(2000);     // wait for two seconds

}