Controlling Nema 17 stepper with pololu A4988

Other Hardware Robotics
1

Hi , :slight_smile:

I have two steppers I need to test using A4988 Stepper Motor Drivers and Arduino.

STEPPERS SPECS

Nema 17 stepper motor :

200 steps per revolution (1.8 deg/step)
2 Phase bipolar 4 wires
Rated Voltage 2V DC
Rated Current 1.2A

Nema 17 stepper motor:

200 steps per revolution (1.8 deg/step)
2 Phase 4 wires
Rated Voltage 4.83V
Rated Current 0.84A

I have connected the motors countless times according to the diagram in the link below

My circuit is powered by a 9V battery, the direction and step pins are connected to pin 8 and 9 respectively, on the Arduino. I am using a UNO board and I am quite sure that the wiring is correct unless something really important isn't mentioned on the diagram. But no matter what demo code I run, the motor just vibrates and makes a scary noise but the shaft doesn't rotate :frowning: . I really can not identify my problem, need help :confused:

2

The small, rectangular 9V batteries are totally unsuitable for either the Arduino or motors.

Motors and the Arduino should always be powered separately. You will also need a substantial power supply or a reasonably good sized battery supply to run motors. A 6-cell NiMH RC hobby pack would work for a while.

Carefully follow the instructions on the Pololu A4988 product page for wiring AND for setting the current limit.

3

the 9V battery only powers the motor through VMOT and GND on the driver and the arduino is powered via usb by the computer I think. As I said I am just in the testing phase of my project and this set up isn't permanent. Thanks for the battery suggestion though. I got the motors to rotate with a sample code by reducing the delay a bit but it still makes an annoying sound. I'll try with a better PSU and see what's up. Thank you...