Driving a stepper motor used to be complicated enough when we have to build a driver by ourselves. But since there are many kinds of driver modules out there, driving a stepper motor is not that hard anymore.
In this video, we will learn how to use the A4988 stepper driver.
Control Stepper Motor with A4988 Driver Module & Arduino
For single-stepper-motor applications, a driver like the L298N is fine, but if you want to construct your own CNC machine or 3D printer, you’ll need a dedicated stepper motor driver like the A4988.
Due to the simplicity of the step motor control and the variety of stepping modes provided by the A4988 driver, it is an ideal solution for building applications that require precise and reliable stepper motor control, such as the movement control of beds, heads, and assemblies in various CNC plotting, milling, and 3D printer designs.
The fact that it only requires two pins to control the speed and direction of a bipolar stepper motor like the NEMA 17 is pretty neat, too.
A4988 Stepper Motor Driver Chip
At the heart of the module is a microstepping driver from Allegro – A4988. Despite its small stature (0.8″x0.6″), it packs quite a punch.
The A4988 stepper motor driver has an output drive capacity of up to 35V and ±2A. This allows you to control a bipolar stepper motor, such as the NEMA 17, at up to 2A output current per coil.
Furthermore, the output current is regulated, allowing for noiseless operation of the stepper motor and the elimination of resonance or ringing that is common in unregulated stepper driver designs.
The driver has a built-in translator for easy operation. This reduces the number of control pins to just two, one for controlling the steps and the other for controlling the spinning direction.
The driver offers five different step resolutions: full-step, half-step, quarter-step, eighth-step, and sixteenth-step.
In order to ensure reliable operation, the driver has additional features such as under-voltage, shoot-through, short circuit, overcurrent, and thermal protection.
Microstep Selection Pins
The A4988 driver supports microstepping by dividing a single step into smaller steps. This is achieved by energizing the coils with intermediate current levels.
For example, if you choose to drive the NEMA 17 (with 1.8° step angle or 200 steps/revolution) in quarter-step mode, the motor will produce 800 microsteps per revolution.
These three microstep selection pins are pulled LOW by internal pull-down resistors, so if you leave them unconnected, the motor will operate in full step mode.
Control Input Pins
The A4988 has two control inputs: STEP and DIR.
input controls the microsteps of the motor. Each HIGH pulse sent to this pin drives the motor according to the number of microsteps determined by the microstep selection pins. The higher the pulse frequency, the faster the motor will spin.
DIR input controls the spinning direction of the motor. Pulling it HIGH turns the motor clockwise, while pulling it LOW turns it counterclockwise.
If you want the motor to only turn in one direction, you can connect the DIR directly to VCC or GND.
You can connect any small to medium-sized bipolar stepper motor, such as NEMA 17, to these pins.
Each output pin can supply up to 2A to the motor. However, the amount of current supplied to the motor is determined by the power supply, cooling system, and current limiting setting of the system.
Cooling System – Heatsink
Excessive power dissipation of the A4988 driver IC causes a temperature rise, which could potentially damage the IC if it exceeds its capacity.
Despite having a maximum current rating of 2A per coil, the A4988 driver IC can only supply about 1A per coil without overheating. To achieve more than 1A per coil, a heat sink or other cooling method is required
Usually, the A4988 driver comes with the heatsink. It is recommended that you install the heatsink before using the driver.
Current limiting
Before running the motor, you must limit the maximum current flowing through the stepper coils so that it does not exceed the motor’s rated current.
Driving a stepper motor used to be complicated enough when we have to build a driver by ourselves. But since there are many kinds of driver modules out there, driving a stepper motor is not that hard anymore.
In this video, we will learn how to use the A4988 stepper driver.
Control Stepper Motor with A4988 Driver Module & Arduino
For single-stepper-motor applications, a driver like the L298N is fine, but if you want to construct your own CNC machine or 3D printer, you’ll need a dedicated stepper motor driver like the A4988.
Due to the simplicity of the step motor control and the variety of stepping modes provided by the A4988 driver, it is an ideal solution for building applications that require precise and reliable stepper motor control, such as the movement control of beds, heads, and assemblies in various CNC plotting, milling, and 3D printer designs.
The fact that it only requires two pins to control the speed and direction of a bipolar stepper motor like the NEMA 17 is pretty neat, too.
A4988 Stepper Motor Driver Chip
At the heart of the module is a microstepping driver from Allegro – A4988. Despite its small stature (0.8″x0.6″), it packs quite a punch.
The A4988 stepper motor driver has an output drive capacity of up to 35V and ±2A. This allows you to control a bipolar stepper motor, such as the NEMA 17, at up to 2A output current per coil.
Furthermore, the output current is regulated, allowing for noiseless operation of the stepper motor and the elimination of resonance or ringing that is common in unregulated stepper driver designs.
The driver has a built-in translator for easy operation. This reduces the number of control pins to just two, one for controlling the steps and the other for controlling the spinning direction.
The driver offers five different step resolutions: full-step, half-step, quarter-step, eighth-step, and sixteenth-step.
In order to ensure reliable operation, the driver has additional features such as under-voltage, shoot-through, short circuit, overcurrent, and thermal protection.
Microstep Selection Pins
The A4988 driver supports microstepping by dividing a single step into smaller steps. This is achieved by energizing the coils with intermediate current levels.
For example, if you choose to drive the NEMA 17 (with 1.8° step angle or 200 steps/revolution) in quarter-step mode, the motor will produce 800 microsteps per revolution.
These three microstep selection pins are pulled LOW by internal pull-down resistors, so if you leave them unconnected, the motor will operate in full step mode.
Control Input Pins
The A4988 has two control inputs: STEP and DIR.
input controls the microsteps of the motor. Each HIGH pulse sent to this pin drives the motor according to the number of microsteps determined by the microstep selection pins. The higher the pulse frequency, the faster the motor will spin.
DIR input controls the spinning direction of the motor. Pulling it HIGH turns the motor clockwise, while pulling it LOW turns it counterclockwise.
If you want the motor to only turn in one direction, you can connect the DIR directly to VCC or GND.
You can connect any small to medium-sized bipolar stepper motor, such as NEMA 17, to these pins.
Each output pin can supply up to 2A to the motor. However, the amount of current supplied to the motor is determined by the power supply, cooling system, and current limiting setting of the system.
Cooling System – Heatsink
Excessive power dissipation of the A4988 driver IC causes a temperature rise, which could potentially damage the IC if it exceeds its capacity.
Despite having a maximum current rating of 2A per coil, the A4988 driver IC can only supply about 1A per coil without overheating. To achieve more than 1A per coil, a heat sink or other cooling method is required
Usually, the A4988 driver comes with the heatsink. It is recommended that you install the heatsink before using the driver.
Current limiting
Before running the motor, you must limit the maximum current flowing through the stepper coils so that it does not exceed the motor’s rated current.
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