NEW PRODUCT – Adafruit A4988 Stepper Motor Driver Breakout Board
Stepper motors are used for CNC machines, 3D printers, and whenever else one needs precise, powerful motion. 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 precise 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 to 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.
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 other Single Board Computer
- 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 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
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 onto 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.
