Motors

28BYJ-48 stepper with ESP32

If your 28BYJ-48 only buzzes and shakes, the likely cause is the pin order. AccelStepper needs IN1, IN3, IN2, IN4, and not the order printed on the board. Change that in the constructor before you check anything else. The example already has it.

This small geared motor costs very little and comes with a ULN2003 driver board. It takes four GPIOs and 5 V. The ULN2003 inputs work from 3.3 V logic, but the motor still needs 5 V, and it can pull about 250 mA. One motor on a strong supply may be fine. If the display board resets when it starts, use a separate 5 V supply and join the grounds.

Sources give different step counts: 4096 per output turn in half-step mode and 2048 in full-step mode. The example uses half steps, so 1024 steps per second gives about 15 RPM, a practical top speed. It is slow and has gearbox backlash, so it suits valves, blinds, dials and rotating displays better than anything that needs precision or speed. Going faster usually makes it skip, without warning. The coils stay powered between moves, and the sources warn that a long hold heats both motor and board, so turn the outputs off when it stops. Four GPIOs is a lot on a parallel RGB board, so check the board page first.

#include <AccelStepper.h>

// Note the order: IN1, IN3, IN2, IN4
AccelStepper stepper(AccelStepper::HALF4WIRE, 4, 6, 5, 7);
const long STEPS_PER_TURN = 4096;

void setup() {
  stepper.setMaxSpeed(1000);
  stepper.setAcceleration(400);
  stepper.moveTo(STEPS_PER_TURN);
}

void loop() {
  if (stepper.distanceToGo() == 0) {
    stepper.disableOutputs();            // stop heating the coils
    delay(1000);
    stepper.enableOutputs();
    stepper.moveTo(-stepper.currentPosition());
  }
  stepper.run();
}

Use this information at your own risk. It is for general guidance only: the example code compiles, but it has not been tested on every part, and modules differ between sellers. Check the manufacturer's data before you build. Product names belong to their owners, and LCD Ultra Pro is not affiliated with them. See our Terms.