Adafruit A4988 Stepper Motor Driver Breakout Board

The Adafruit A4988 Stepper Driver Breakout offers simple two-pin control, built-in microstepping (up to 1/16), onboard DIR/STEP LEDs for signal feedback, and terminal blocks for easy wiring. With 2A max current and adjustable limits, it’s ready for serious motion projects.

Stepper motors are used in CNC machines, 3D printers, and other applications where precise, powerful motion is required. But to get good behavior from steppers, you need a motor driver chip that can provide high bursts of current, and for smooth motion, be able to PWM that current for microstepping support. You can DIY this with a lot of timers, a microcontroller, and an  H-Bridge chip – or you could take the easy way out and use an Adafruit A4988 Stepper Motor Driver Breakout Board, which makes controlling stepper motors easy-breezy.

All you need is two output pins, no timers, PWM, or real-time microcontroller. Set the DIRection pin high or low to set the spin orientation. Then toggle the STEP pin to take one step or microstep at a time. You can set whether you want to go fast with single-step mode or improve the motion precision with 1/4, 1/8, or 1/16 microstepping per STEP toggle. By default, the driver is set to 1/16 microstep mode; you can change it by tying the MS1/MS2/MS3 pins low, either with jumpers or with 3 more output pins. The step/microstep mode can even be adjusted on the fly! LEDs on the DIR and STEP pins let you get visual feedback of your motor signal.

The Allegro A4988 is a popular driver chip, with small breakout boards used in many 3D printers. Those breakouts are great for plugging into motherboards, but are a little tough to use for prototyping. Our version comes with terminal blocks for the motor power and stepper wires, plus nicely labeled pins for control and mounting holes.

We fabricated the board with 2 oz copper to give it a hand with the 2A-max current that this driver can handle. To use the current limiting capability, twist the onboard potentiometer: when all the way to the right, we can get up to 2A max. Note that the higher the currents, will heat up both the motor driver and stepper so you may need to add heatsinking to the chip. We don’t include a heatsink, but you can get a tall ~80ºC/W or short ~90ºC/W heatsink to attach on top.

Comes as one assembled and tested breakout plus a small strip of header. You’ll need to do some light soldering to attach the header to the breakout PCB. Microcontroller, motors, and power supply not included. You will need some sort of driver board that will toggle the DIR/STEP pins for you.

Features

• Allegro A4988 DMOS microstepping driver with translator and overcurrent protection
• Motor voltage from 8V to 35VDC
• Vdd/Logic voltage from 3V to 5V, use with anything from an Arduino-compatible or ESP32 to Raspberry Pi  to other Single Board Computers
• Terminal screw block connections for easy VMotor power and 4-wire bi-polar stepper motor connection with 26-20AWG slots, 2.54mm / 0.1′ spacing
• Control steppers using only two pins: DIRection and STEP
• Defaults to 1/16 microstep mode, change by grounding MS1/MS2/MS3 pins (see A4988 datasheet for pin configuration)
• Red and Green LEDs on DIR signal to let you know forward or backward motion
• Yellow LED on STEP to let you know that the motor driver is being moved
• Sleep, Reset, and Enable control lines for low power/deactivation
• Potentiometer to set current limiting, up to 2A
• 22uF 50V electrolytic capacitor on motor power
• 2 Oz copper for better current carrying and heatsinking
• Four mounting holes

Resources 

• Primary Guide: Adafruit A4988 Stepper Motor Driver Breakout Board

Package Contents

• 1x Adafruit A4988 Stepper Motor Driver Breakout Board
• 1x 10-pin header