This is the most commonly used stepper motor in low power industrial and most famously in hobbyist projects.

The statement #defineis used to give a name to a constant value. The compiler will replace any references to this constant with the defined value when the program is compiled. So everywhere you mention motorPin1, the compiler will replace it with the value 8 when the program is compiled. // Motor pin definitions: Now we will create an instance of the Stepper library called motor() and pass the steps per revolution and the individual motor input pins as arguments. Make sure you specify the input pins in their correct sequence. It is IN1, IN3, IN2, and IN4 for 28BYJ-48 stepper motor. Stepper motor(steps_per_rev, IN1, IN3, IN2, IN4); Stepper motors can be driven in different modes and they have a specific gear ratio. Both factors have an influence on the number of steps per revolution. For this example, we shall drive the motor in a mode known as the full step mode, with each step corresponding to a rotation of 11.25 degrees according to the datasheet. That means there are 32 steps per revolution (360/11.25 = 32). In addition, the manufacturer has specified a gear ratio of 64:1 for the 28BYJ-48 stepper motor. How it works? If left unhooked, the enable pin is floating or pulled to ground-- in either case the A4988 is ready to operate a motor without connecting this pin. It provides several examples that are compatible with the ESP32. Just make sure you initialize a stepper object with the right pins: AccelStepper stepper (AccelStepper::FULL4WIRE, 19, 5, 18, 17);Write program. I'm assuming your stepper is hooked to the x-axis on the CNC shield. (see below for other UNO to CNC shield pin assignments) Recommneded reading: ULN2003 introduction, pinout, example and features Stepper Motor Driver Module Pinout

yes, good call. I was using 5V from the Arduino, in error; but all morning I have now been using a bench power supply for the motor, 5V at 350mA. In this case I called the stepper motor ‘myStepper’ but you can use other names as well, like ‘z_motor’ or ‘liftmotor’ etc. Stepper liftmotor = Stepper(stepsPerRevolution, 8, 10, 9, 11);. You can create multiple stepper motor objects with different names and pins. This allows you to easily control 2 or more stepper motors at the same time. Full Disclosure: One A4988 stepper driver was destroyed with reverse polarity during the making of this instructable.In the following three examples I will show you how you can control both the speed, the direction and the number of steps the stepper motor should take. In these examples I will be using the AccelStepper library. Plug a properly pinned out (via crossover cables or re-populating the stepper's header) 28BYJ-48 stepper motor into the 4 outputs on each A4988 you have plugged in. While, being careful to not connect the red wire. The next loop function is where we will write our code to drive the motor. For the first line of the loop, we set the speed of one revolution to one per minute. I applied a 12V reverse polarity to to my shield during this step, fried an A4988 and thankfully nothing else. I then simply added a new A4988 and I re-powered it correctly (+ to +, - to -), it seems fine. But, a possibly damaged shield like this should be marked as such (Sharpied note to self), so it doesn't wind up accidentally getting put into service in an end project someday.