OEMULN2003 Board

The ULN2003 Stepper Motor Driver Module is a driver board designed for small four-phase, five-wire unipolar stepper motors. It operates with a 5-12VDC motor supply and is particularly suitable for controlling 28BYJ-48 motors using Arduino, Raspberry Pi, ESP32 and other microcontroller platforms.

Technical description

The board is based on the ULN2003A integrated circuit, which contains seven Darlington transistor pairs with open-collector outputs. Four channels are used on this module to switch the four phases of the stepper motor.

The IN1, IN2, IN3 and IN4 inputs connect to four digital outputs of the microcontroller. The motor direction, speed and position are controlled by applying the appropriate activation sequence to these inputs.

The module includes an XH-5P socket for direct connection of a compatible 28BYJ-48 stepper motor. Four indicator LEDs display the activation status of each phase and assist with checking the operating sequence.

The integrated protection diodes of the ULN2003A suppress the reverse voltage generated by the motor windings during switching. The driver board allows the microcontroller to control the load without passing the motor current through its digital output pins.

Typical applications

Suitable for Arduino and Raspberry Pi projects, STEM education, small robotic mechanisms, rotary indicators, automation systems, camera mechanisms, models, low-power valves and positioning applications.

Compatibility note

The module is designed for four-phase, five-wire unipolar stepper motors such as the 28BYJ-48. It is not suitable for four-wire bipolar stepper motors, which require an H-Bridge driver such as the A4988, DRV8825 or equivalent.

Power supply note

The supply voltage must match the rated voltage of the connected motor. A 5V 28BYJ-48 motor must be powered from 5VDC and must not be connected to a 12VDC supply. The module does not include a voltage regulator or step-down converter.

When a separate motor power supply is used, its ground must be connected to the microcontroller ground.

Package note

The package includes only the ULN2003 driver board. The stepper motor and connection wires are not included.

Dimensions: approximately 40x21mm.

Weight: approximately 0.006 kg.