28BYJ-48 stepper with Raspberry Pi Pico

Wiring for the 28BYJ-48 stepper + ULN2003 driver on the Raspberry Pi Pico (RP2040, 3.3 V logic), chosen with the same pin rules BoardPilot uses: default buses first, and no pins that are used for flash, USB, the debugger or booting.

Wiring

28BYJ-48 stepper pin	Role	Raspberry Pi Pico pin	Notes
IN1	Input to the part	GP15
IN2	Input to the part	GP14
IN3	Input to the part	GP13
IN4	Input to the part	GP12
-	Ground	GND
+	Power	VBUS	Motor supply 5 V: use VBUS (about 240 mA)

Check before you power it on

Supply: 5 V from the VBUS pin.
Motors, servos, relays and LED strips can draw more current than the Raspberry Pi Pico’s pins or USB can give. Power them separately and connect the grounds together.

Test code (Arduino)

// Library: Stepper (built in)
#include <Stepper.h>

// 2048 steps per turn; note the IN1, IN3, IN2, IN4 order for this motor
Stepper motor(2048, 15, 13, 14, 12);

void setup() {
  motor.setSpeed(10);  // rpm
}

void loop() {
  motor.step(2048);   // one turn
  delay(500);
  motor.step(-2048);  // and back
  delay(500);
}

Arduino board: rp2040:rp2040:rpipico. If the board is not found, hold the BOOTSEL button while plugging in the USB cable.

Questions

Which Raspberry Pi Pico pins do I use for the 28BYJ-48 stepper?

IN1 → GP15, IN2 → GP14, IN3 → GP13, IN4 → GP12, - → GND, + → VBUS.

Does the 28BYJ-48 stepper work with the Raspberry Pi Pico at 3.3 V?

Yes: the 28BYJ-48 stepper runs at 5 V and the Raspberry Pi Pico uses 3.3 V signals, so no level shifting is needed.

BoardPilot checks this wiring in 3D as you build it, and finds crossed or missing wires on the real board.

Download BoardPilot

Full Raspberry Pi Pico pinout · 28BYJ-48 stepper + ULN2003 driver: all pins and data

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